French Construction Cost Index (ICC): 2,084 points in Q1 2026

The construction cost index (indice du coût de la construction, ICC) for the first quarter of 2026 (Q1 2026) stands at 2,084 points, on a base of 100 in the fourth quarter of 1953, for metropolitan France. Insee, the French national statistics institute, published this figure on 24 June 2026 (Informations rapides no. 156) and it is reproduced in a notice in the Official Journal (Journal officiel) no. 0150 of 28 June 2026. The index is up 1.26% over one quarter and down 2.89% year on year. No more recent value exists to date: the ICC for the second quarter of 2026 is announced for the end of September 2026.

• Index: ICC (national construction cost index)
• Quarter: Q1 2026 (first quarter of 2026)
• Value: 2,084 points
• Base: 100 in the fourth quarter of 1953
• Quarterly change: +1.26%
• Year-on-year change: -2.89%
• Insee release: 24 June 2026, Informations rapides no. 156
• Official Journal: no. 0150 of 28 June 2026
• Next release: end of September 2026 (Q2 2026), with no precise date announced
• Scope: metropolitan France

The latest published value of the construction cost index is the one for the first quarter of 2026: 2,084 points on a base of 100 in the fourth quarter of 1953. It is up 1.26% on the previous quarter and down 2.89% year on year.

Year-on-year changes published by Insee for Q1 2026 and Q4 2025; calculated from the Insee values for Q1 2025.

Insee releases the figure first in its Informations rapides collection, on 24 June 2026 for this quarter. It is then reproduced in a notice concerning the construction cost index for the first quarter of 2026 (avis relatif à l'indice du coût de la construction du premier trimestre de 2026), published in Official Journal no. 0150 of 28 June 2026. That notice is the one to cite in an indexation letter or a lease amendment: it is dated, it is authoritative as to the value retained, and it states the reference base.

Insee publishes the ICC on two bases, which explains the contradictory values circulating for one and the same quarter.

The reference series uses a base of 100 in the fourth quarter of 1953. That is the series worth 2,084 in the first quarter of 2026, the one that appears in the Official Journal, and the one referred to in indexation clauses going back decades. A second series, rebased on the year 2021, gives 112.4 for the same quarter: it is used for comparisons between construction indices, almost all of which are expressed on a 2021 base.

Working rule: base 100 in the fourth quarter of 1953 for any contractual use (lease, amendment, works contract, indexation letter); base 100 in 2021 for trend analysis or comparison between indices. A calculation that mixes the two bases is arithmetically wrong, even where both figures are individually correct.

The error typically occurs where a contract records a starting index taken from the 1953 base and this is then set against a reference index taken from the 2021 base: the resulting ratio has no economic meaning. Before any calculation, read again the base stated in the clause, and failing that, the base given in the Official Journal notice for the year of signature.

The quarterly and year-on-year rates of change in the table are a direct arithmetical calculation on the values published by Insee. Only the year-on-year changes for the first quarter of 2026 and the fourth quarter of 2025 appear as such in the Insee release.

Long ICC series since 2010 and annual averages#

Complete series on a base of 100 in the fourth quarter of 1953, from the first quarter of 2010 to the first quarter of 2026.

The quarterly values are those published by Insee. The annual averages are an arithmetic mean of the four quarters of the year, calculated by the firm: Insee does not publish an annual average of the ICC. For 2026, with only one quarter published, no annual average can be calculated.

This average is distinct from the average of the last four indices, a separate series published by Insee that some clauses refer to expressly: the first covers a calendar year, the second the last four quarters known at the review date, whichever they are.

The recent peak is in the first quarter of 2024, at 2,227 points, after two years of increases, at annual rates ranging from 3.39% to 8.80% depending on the quarter. The low point of the recent cycle is in the third quarter of 2025, at 2,056 points, a fall of 7.7% from the peak. The index has been recovering slowly since then: +0.10% and then +1.26% over the last two quarters. The 2.89% annual fall recorded in the first quarter of 2026 therefore reflects the comparison with a high level, at a time when the quarterly trend has already turned.

The four-quarter average of the ICC: what it is used for in a clause#

Some indexation clauses, in particular in works contracts and in professional leases drafted by institutional landlords, do not refer to a single quarterly index but to the average of the last four published indices. The aim is to smooth quarterly volatility, which has reached 3.61% in a single quarter (third quarter of 2022) and a gap of up to 4.6 percentage points between two consecutive quarterly changes (+1.80% in the first quarter of 2025, then -2.80% in the second quarter of 2025).

Calculation from the Insee values, on the last four published indices:

(2,084 + 2,058 + 2,056 + 2,086) / 4 = 2,071.00

That average is a calculation, not a figure published by Insee in that form. It should only be used where the clause expressly provides for it, and by following to the letter the four-quarter window it defines.

Despite its name, the ICC does not measure a cost. It measures the change in the construction price of new buildings used mainly as non-communal housing, in metropolitan France. It is the price paid by the client (maître d'ouvrage) for the works themselves, as observed in the contracts surveyed, and not the sum of the expenses borne by the contractor in producing them.

The distinction is structural, because it determines what the index captures and what it ignores. The observed price excludes:

• land costs, in other words the price of the plot;
• ancillary property development costs;
• transfer duties;
• financial costs.

The ICC therefore does not measure the cost of a property development project, nor a developer's cost price, nor the change in materials prices taken in isolation, nor renovation works. An index that rises while materials prices fall, or the reverse, is simply measuring a different quantity.

The ICC is published every quarter, during the third month following the quarter measured, and is then reproduced in a notice in the Official Journal a few days later. The sequence of the four stages explains the lag:

1. End of the quarter measured. For the first quarter of 2026, 31 March 2026.
2. Publication by Insee, in the Informations rapides collection, during the third month following the quarter measured. Here, 24 June 2026.
3. Notice in the Official Journal, a few days later. Here, 28 June 2026.
4. The index becomes enforceable in contractual relations as soon as it is officially published.

Practical consequence: depending on the date, the latest known index relates to a quarter that closed between three months earlier (on the day of publication) and six months earlier (on the eve of the next release). A clause requiring "the last index published at the date of review" therefore never refers to the current quarter. A clause referring to "the index of the quarter of the review" means in practice waiting for publication, unless it is read as referring to the last index published.

ICC for the second quarter of 2026: release date and expected value#

The ICC for the second quarter of 2026 has not yet been published. Insee announces it for the end of September 2026, with no precise date announced. The latest usable index remains the one for the first quarter of 2026: 2,084 points on a base of 100 in the fourth quarter of 1953. No value for the second quarter of 2026 can legitimately be circulating before that release: a figure presented today as the ICC for Q2 2026 is either a projection or a confusion with another index. This page will be updated as soon as the notice appears in the Official Journal.

For a lease entered into or renewed on or after 1 September 2014, the statutory cap on the three-yearly review and on the rent of the renewed lease is measured against the ILC or the ILAT, never against the ICC. The ICC does, however, remain a lawful index for an escalation clause (clause d'échelle mobile) in an agreement relating to a built property. To place a lease, work through the following in order.

1. Was the lease entered into or renewed before, or on or after, 1 September 2014? Act no. 2014-626 of 18 June 2014 amended articles L. 145-38 and L. 145-34 of the Commercial Code: since that date, the statutory cap on the three-yearly review and on the rent of the renewed lease is measured by reference to the ILC or the ILAT. The ICC no longer appears there.
2. What activity is carried on in the premises? The ILC (indice des loyers commerciaux, the commercial rent index) covers commercial activities and craft activities, within the meaning of article D. 112-2 of the Monetary and Financial Code. The ILAT (indice des loyers des activités tertiaires, the services rent index) covers service activities other than commercial and craft ones, which include in particular the regulated professions (professions libérales) and activities carried on in logistics warehouses. It is the nature of the activity that governs the choice, not the floor area or the rent level, registration in the national business register being no more than an indication for that classification. The difference between the ILC and the ILAT turns on that classification.
3. Does the clause name the ICC expressly? Article L. 112-2, first paragraph, second sentence, of the Monetary and Financial Code deems any clause providing for indexation on the change in the national construction cost index published by Insee to be directly connected with the subject matter of an agreement relating to a built property. Referring to the ICC in an escalation clause is therefore lawful by statutory presumption.
4. On what legal basis is the adjustment claimed? An annual indexation operating automatically by the effect of the escalation clause is not the same operation as a three-yearly review claimed on the basis of article L. 145-38 of the Commercial Code.

The distinction is as follows. The ICC remains a lawful index for an escalation clause in an agreement relating to a built property. The basis for that distinction is textual: the Act of 18 June 2014 amended articles L. 145-34 and L. 145-38 of the Commercial Code, it did not touch article L. 112-2 of the Monetary and Financial Code, which continues to presume the ICC to be directly connected with the subject matter of an agreement relating to a built property. It has, however, been removed from the statutory cap on the three-yearly review and on renewal, for leases entered into or renewed since 1 September 2014. Where Insee writes in its first-quarter 2026 release that the ICC "is no longer among the indices usable for the indexation of commercial leases", that wording refers to the second mechanism. This is the reading we adopt; it does not rule out a landlord or a tenant disputing it, and a clause referring to the ICC is worth re-examining on any renewal.

The two mechanisms coexist: an escalation clause referring to the ICC operates on its own terms, without removing the statutory cap where a three-yearly review is claimed on the basis of article L. 145-38.

A landlord who has switched a lease to the ILC has not left the ICC behind: it has been diluted. Since the fourth quarter of 2021, the ILC has been composed 75% of the consumer price index excluding tobacco and rents, and 25% of the ICC (Insee, Informations rapides no. 154 of 24 June 2026). The ILAT for its part combines 50% consumer prices, 25% construction cost and 25% gross domestic product in value terms (Insee, Informations rapides no. 155 of 24 June 2026).

The 2.89% year-on-year fall in the ICC therefore mechanically helps to contain the ILC, whose annual change stands at -0.45% in the first quarter of 2026. Over the same period, the ILAT is up 0.09% year on year.

The IPEA value for the first quarter of 2026 is provisional (Insee, Informations rapides no. 131 of 28 May 2026). The ICP-F, published in Informations rapides no. 157 of 24 June 2026, is up 1.4% over the quarter: it is a production cost index, not to be confused with the ICC, which is a price index. For residential rents, the reference index is the IRL (indice de référence des loyers), which stands at 148.37 in the second quarter of 2026 and is up 1.15% year on year; its next release is set for 15 October 2026 at 8.45 a.m.

The usual contractual formula is a simple ratio of indices:

Revised rent = Current rent x (Reference index / Starting index)

Everything turns on the choice of the two indices, not on the multiplication.

1. Take the starting index exactly as it appears in the contract, with its quarter and its base. If the clause does not fix it, it is the index of the reference quarter of the last review actually applied.
2. Check the periodicity stipulated. Article L. 112-1 of the Monetary and Financial Code deems unwritten any stipulation providing for a period of index variation longer than the interval between two reviews. An annual indexation is calculated over a four-quarter gap, no more.
3. Identify the last index published at the date of review, allowing for the publication lag described above.
4. Apply the ratio between the reference index and the starting index, without rounding the indices themselves.
5. Document the calculation in the notification: quarters used, values, base, Official Journal publication dates, result. That record is what allows the review to be shown to be properly carried out if it is challenged.

Illustrative calculation no. 1 (annual indexation on the ICC). The figures below are a teaching example, built to show the mechanics, and not a real case.

Current annual rent: 20,000 euros. Starting index: ICC for the first quarter of 2025, that is 2,146. Reference index: ICC for the first quarter of 2026, that is 2,084. The gap between the two quarters is indeed four quarters, which corresponds to an annual review.

• Ratio of indices: 2,084 / 2,146 = 0.971109
• Revised rent: 20,000 x 0.971109 = 19,422.18 euros
• Difference: -577.82 euros a year, that is -2.89%

Illustrative calculation no. 2 (the same annual rent indexed on the ILC, with a quarterly review). Like the previous one, this is a teaching example and not a real case. The two illustrations are independent: they do not concern the same review periodicity and their results are not directly comparable.

Current annual rent: 20,000 euros. Starting index: ILC for the fourth quarter of 2025, that is 134.62. Reference index: ILC for the first quarter of 2026, that is 135.26. The one-quarter gap between the two indices corresponds to a quarterly review.

• Ratio of indices: 135.26 / 134.62 = 1.004754
• Revised rent: 20,000 x 1.004754 = 20,095.08 euros
• Difference: +95.08 euros

Where the review becomes a cash-flow issue, it is prepared at the same time as the rest of the lease: on this point, see how to negotiate the indexation of a commercial lease.

One last safeguard operates alongside: where a lease contains an escalation clause, article L. 145-39 of the Commercial Code allows a review to be claimed as soon as the rent has been increased or reduced by more than a quarter compared with the price previously fixed by contract or by court decision. For leases entered into or renewed since 1 September 2014, the resulting variation may not lead to increases exceeding, for any one year, 10% of the rent paid during the previous year.

Act no. 2026-403 of 26 May 2026 created article L. 145-38-1 of the Commercial Code, which came into force on 28 May 2026. Its text is short and its effect is clear:

"By way of derogation from article L. 112-1 of the Monetary and Financial Code, a clause whose object or effect is to cap, in the same proportions upwards and downwards, the annual variation of the commercial rent index taken into account for the review of the rent under articles L. 145-38 and L. 145-39 of this code is authorised in leases of commercial premises."

The authorisation is doubly conditional: the cap must apply to the ILC, and it must operate in the same proportions upwards and downwards. That is the line drawn by the Court of Cassation since its judgment of 14 January 2016 (Third Civil Chamber, appeal no. 14-24.681, published): a clause that excludes reciprocity of variation and stipulates that the rent may only be revised upwards is deemed unwritten. The legislature has secured the symmetrical tunnel, which remained legally fragile in the light of the general prohibition on indexation laid down by article L. 112-1 of the Monetary and Financial Code, without opening the door to unilateral floor clauses.

Article 62 of the Act contains no transitional provision specific to article L. 145-38-1, whereas other provisions of the same Act carry their own rules on application over time. As matters stand, the tunnel clause may be stipulated in leases, amendments and renewals entered into after the text came into force on 28 May 2026. Its scope in relation to clauses contained in earlier leases has not been settled: it must be assessed case by case.

Three defects bring an indexation clause down: asymmetry, period distortion and an index foreign to the clause. All three concern the index or the way it is handled, not the principle of indexation itself. On the general validity of a price review clause, the substitute index or hardship, see the page on how to draft a valid price review clause.

1. Asymmetry. A clause that operates only upwards is set aside on the basis of article L. 112-1 of the Monetary and Financial Code. In its judgment of 14 January 2016 (Third Civil Chamber, appeal no. 14-24.681, reported in the official law reports (Bulletin des arrêts)), the Court of Cassation held that an indexation clause excluding reciprocity of variation distorts the normal operation of indexation and must be deemed unwritten. The sanction is indeed the one provided by that text, and not nullity under the general law: the distinction governs the regime of the action and the extent of any restitution, a point to be checked case by case. The label "unfair term" sometimes put forward belongs to a different body of rules: the usual basis is monetary and financial law, not consumer law.

2. Period distortion. Any stipulation providing for a period of index variation longer than the time elapsing between each review is deemed unwritten. In a judgment of 6 February 2020 (Third Civil Chamber, appeal no. 18-24.599, published), the Court of Cassation held that this prohibition applies from the very first indexation, and not only to later reviews, and that, since the distortion affected only the first review, only the stipulation creating it is deemed unwritten: the clause continues to have effect for subsequent indexations.

3. An index foreign to the clause. Applying the ILC to a lease that refers to the ICC, or the reverse, cannot be put right by a simple letter: the index is a term of the contract, and substituting it requires in principle an amendment signed by both parties; where the contractual index has disappeared or is prohibited, its substitution follows a distinct regime, which must be examined clause by clause.

How far does the sanction go? The principle is severability: only the prohibited stipulation is deemed unwritten, and the rest of the clause survives. The Court of Cassation restated this on 12 January 2022 (Third Civil Chamber, appeal no. 21-11.169, published), partly quashing a decision that had deemed the whole clause unwritten, and again on 19 June 2025 (Third Civil Chamber, appeal no. 23-18.853, published), holding that the words "upwards only" could be struck out without affecting the coherence of the clause. The exception is indivisibility, applied where the prohibited stipulation cannot be struck out without depriving the clause of coherence: that is the solution of the judgment of 14 January 2016, which deems the clause unwritten in its entirety. On 30 June 2021 (Third Civil Chamber, appeal no. 19-23.038, published), the Court took the opposite course and partly quashed a decision of a court of appeal that had deemed the whole clause unwritten, on grounds unfit to establish indivisibility, in a case where the clause contained an annual 3% limit applicable to the first three years of the lease. The collapse of the entire indexation mechanism therefore requires indivisibility to be properly established.

The ICC has no place in a contract for the construction of an individual house (contrat de construction de maison individuelle, CCMI, the regulated French turnkey house-building contract). Article L. 231-11 of the Construction and Housing Code requires the price review to be calculated by reference to the variation of a national all-trades building index measuring the change in the cost of production factors. Article R. 231-6 designates that index: it is the BT 01 index, published monthly in the Official Journal by the minister responsible for the economy and finance.

The fate of a CCMI price review turns on three points:

• the contract must adopt one of the two methods provided for by article L. 231-11: either a review based on the variation of the index between signature and the date fixed by article L. 231-12, or a review on each payment, within a limit expressed as a percentage of the variation of the index. For that second method only, the Act requires a limit of between 60% and 80%, which article R. 231-6 of the same code sets at 70%;
• the base index is the last index published on the day the contract is signed, which rules out choosing a more favourable index retrospectively;
• absent the statements required by article L. 231-11, the price stated in the contract is not revisable. The sanction does not bear on the calculation: it removes the right to a review altogether.

For the accounting and tax mechanics specific to businesses in the sector, see our construction industry accounting guide.

As an extension of an accounting engagement, we review your indexation clause: re-reading of the clause and its schedules, identification of the applicable index in the light of the date the lease was entered into or renewed and of the activity carried on, verification of the periodicity against article L. 112-1 of the Monetary and Financial Code, calculation of the review and a detailed calculation note. The drafting of legal instruments and the conduct of litigation are matters for your lawyer, with whom we are glad to work.