Quick answer: what does an accountant do for an engineering consultancy?#
A bureau d'études techniques is a professional services firm that designs, calculates and specifies on behalf of a client or another builder, without carrying out the works itself. Its engagements are sold on a fixed-price or time basis, run over several months, and fall under the Syntec collective agreement.
An accountant for such a firm works on four points that general bookkeeping does not settle on its own:
- revenue recognition, on completion or as the contract progresses, with the work in progress and accrued income that follow;
- the research tax credit and JEI base, built from time recorded project by project rather than from invoices issued;
- the price revision clause, indexed on the Syntec index, written into most contracts and rarely applied;
- margin per project, the only reading that tells you whether a contract won was actually profitable.
Bookkeeping, tax and payroll under the Syntec agreement follow.
BET, ESN, architect, works supervisor: four businesses that are not the same#
These four professions are regularly confused, including by accounting firms, although they share neither the same billing model nor the same accounting risks. A bureau d'études techniques sells an intellectual engineering service: calculation notes, sizing, structure, building services, thermal studies, industrial process. It commits engineer hours to a technical deliverable, usually for a fixed price, on assignments that run several months and cross the year end. Fixed price plus duration: that combination triggers everything below.
| Business | What it sells | The dominant accounting issue |
|---|
| Engineering consultancy (BET) | A fixed-price engineering study | Percentage of completion, work in progress, research tax credit |
| IT services company (ESN) | Consultant man-days, time and materials | Daily rate, bench time, Syntec payroll |
| Architect | A regulated design assignment | Fees by phase, insurance, self-employed or corporate regime |
| Works supervisor (maître d'œuvre) | Supervision of the works | Public procurement, ten-year liability |
A BET is not a construction company: everything that touches the building site (multiple VAT rates on works, reverse charge on subcontracting, retention money, the industry holiday fund) belongs to the construction sector, and a construction-site chart of accounts answers none of a consultancy's real questions.
Recognising revenue as the contract progresses: work in progress, accrued income, long-term contracts#
A BET signs a fixed-price study, invoices it against a negotiated schedule (on order, on the preliminary design, on delivery), and its year ends in the middle. The revenue of the year is neither what was invoiced nor what was collected: it is what was produced.
The Plan comptable général (PCG), the French general chart of accounts (ANC regulation 2014-03) and the source of French GAAP, treats these as long-term contracts, in articles 622-1 and following.
The starting point is Article 622-2: a long-term contract is accounted for either under the completed-contract method or under the percentage-of-completion method. That is a choice made by the entity, not an obligation, and as at 1 January 2026 completion is not one of the French benchmark accounting methods. Article 622-3 therefore applies only if you have opted for completion: in that case, and where the outcome at completion can be estimated reliably, the result is recognised by applying the percentage of completion to the outcome at completion, so revenue and margin follow the pace at which the study is actually produced. Article 622-4 organises the fallback: where the outcome cannot be estimated reliably, no profit is recognised and revenue is limited to the costs that contributed to performing the contract. The case for the completion method is one of management reporting and bank readability, not an accounting requirement.
Is the outcome reliably estimated? Article 622-5 gives three criteria:
- the ability to identify clearly the total revenue of the contract;
- the ability to identify clearly the total costs attributable to the contract;
- the existence of management tools, cost accounting and internal control allowing the percentage of completion to be validated and the estimates of costs, revenue and outcome to be revised as the contract progresses.
Our reading. The third criterion is the one nobody reads and everybody suffers: it does not ask for an intention, it asks for a tool. Without project-level cost accounting and time sheets posted by engineer and by contract, a consultancy cannot justify a percentage of completion: it falls into article 622-4, margin flattened to zero on every open contract at the year end. Those same time sheets carry the research tax credit base. One failure, time not posted to a project, brings down both.
Two accounts carry the weight, under their French names in the trial balance. Travaux en cours (TEC), work in progress, records production carried out and not yet recognised as revenue, at production cost and never at selling price. Factures à établir (FAE), accrued income, records revenue earned, matching genuine progress, but not yet invoiced. Symmetrically, deferred income (produits constatés d'avance) neutralises an instalment invoiced ahead of the work actually done. An English-speaking reader should note that both sit on the balance sheet, and that it is their movement across the year end, not the invoicing schedule, that drives the revenue figure. The method chosen applies to all the entity's long-term contracts and is disclosed in the notes to the accounts.
One mechanism deserves particular attention, because it is the only one that reveals a loss-making engagement before delivery: the provision for a loss at completion (provision pour perte à terminaison). As soon as an overall loss becomes probable on a contract, meaning its forecast cost at completion exceeds the price left to invoice, article 622-6 of the PCG requires the whole expected loss to be provisioned, not merely the portion of the current year, whether the firm uses completion or percentage of completion. That is what catches a fixed price drifting before it eats the margin of the healthy contracts.
The underestimated risk is not tax, it is banking: recognition on completion gives a saw-tooth result, hostage to the delivery date of two or three contracts, and the banker reads volatility.
VAT for an engineering firm: on collection by default, on the debits by option#
For a supply of services, VAT is due on collection by default, and exigibility on the debits exists only by option (French tax code, CGI article 269-2-c). An engineering firm therefore remits the tax only once it has been paid, unless it has expressly opted for the debits, in which case the tax becomes due on invoicing.
This combines with percentage-of-completion recognition in a way many files miss: accrued income is not an invoice. The revenue earned booked as FAE at the year end is accounting revenue, but it has not yet been invoiced, so it makes no VAT due, even under the debits regime. VAT follows the invoice and the payment, not the accounting progress. Confusing the two leads either to remitting a tax that is not due, or to forgetting one that is.
The collection-versus-debits arbitrage is concrete for a BET whose clients, often public bodies, pay at 60 or 90 days. Staying on collection protects cash: the tax is remitted only once the client has paid. Opting for the debits simplifies the follow-up and lets a B2B client deduct on receipt of the invoice, but advances the VAT before collection. In every case, a deposit collected makes the VAT due immediately, even on the debits.
The e-invoicing reform enters that choice, but not on the timetable usually quoted. From 1 September 2026, a VAT-registered engineering firm must only be able to receive an electronic invoice, whatever its size. The obligation to issue invoices and report transaction data applies at that date to large and mid-sized companies only: for SMEs and micro-businesses it starts on 1 September 2027. Payment data reporting, moreover, concerns certain cases rather than every transaction. We size the cash effect against the simplicity before any option is filed.
The Syntec index: the price revision clause many consultancies never activate#
The Syntec index is published monthly by the Fédération Syntec, the French federation of engineering, digital and consulting firms. Contrary to a widespread belief, it is not published by INSEE, the national statistics institute: confusing the two produces clauses that cannot be applied.
It measures the cost of essentially intellectual labour, which makes it the natural index of an engineering contract, used contractually for price revision. The usual formula is P1 = P0 x (S1 / S0), S0 being the reference index at signature and S1 the index of the revision month. A linking coefficient exists for contracts signed before August 2022: check the index base before calculating.
A BET signs a multi-year study in year N on a given engineer cost, and delivers in year N+2 with salaries that have risen meanwhile. Without a revision clause, wage inflation comes out of its margin. In the files we take over: no clause, a clause never applied for lack of follow-up, or a clause drafted on an index that does not exist. Price revision is a margin item: calculate it, invoice it, monitor it.
CIR and CII: the research tax credit base has narrowed#
The crédit d'impôt recherche (CIR) is the French research tax credit, offset against corporate income tax. For a BET it is both an opportunity and a trap: the activity produces technical knowledge, but the service sold to the client is not, in itself, research. What qualifies is the removal of a scientific or technical obstacle, not the application, however skilled, of known methods to a client project. Separating the two in the recorded time is the only way to make the base defensible. Beside it, the crédit d'impôt innovation (CII) covers prototypes and pilots of new products.
The parameters as at 1 January 2026 (French tax code, CGI article 244 quater B):
| Parameter | Value |
|---|
| CIR rate | 30% up to €100 million of research expenditure, 5% above (50% in the overseas departments) |
| Flat-rate operating expenses | 75% of depreciation charges + 40% of staff costs |
| CII rate (mainland France) | 20%, base capped at €400,000 a year, so €80,000 of credit at most |
| Filing | Form 2069-A-SD, attached to the liasse fiscale, the annual French tax return package |
Two changes must be built into the calculation, or the credit is overstated. The flat rate on staff costs fell from 43% to 40% for expenditure incurred since 15 February 2025. Several items have also left the base: patent filing, maintenance and defence costs, technology watch (previously capped at €60,000), and the doubling of the base for young doctorate holders. The Finance Act for 2026 maintained the scheme, without reforming the rates.
One confusion deserves to be denied without hedging, because it circulates as far as investor business plans: there is no enhanced CIR rate attached to JEI status. The only enhanced rates are geographic; for the CII they concern the overseas departments (60%) and Corsica (35% or 40%). A consultancy that builds its cash forecast on a "JEI-boosted" credit will discover the gap when the refund arrives.
Size it up with our CIR and JEI simulator, then secure the base and the documentation with our innovation funding assignment.
What gets looked at first in an engineering consultancy's CIR file#
A BET has a feature that sets it apart from a laboratory or a software publisher: on the same day, its engineers work on billable client assignments and, sometimes, on removing a technical obstacle. Both come out of the same minds, the same offices and the same time sheets. That porosity is exactly what makes the base fragile when it is not traced.
The border between the assignment and the research. A fixed-price study, however technically demanding, remains the application of known methods to a particular case: difficulty alone does not make it eligible. What is eligible is the work carried out to remove a scientific or technical uncertainty that the state of the art does not allow you to resolve, in the sense of the Frascati Manual, the OECD reference the tax authority relies on to assess this kind of obstacle. A consultancy that declares a percentage of its engineering revenue, without having isolated the corresponding hours, is presenting a base it will not be able to defend.
Hours, not invoices. The base is built from staff costs allocated to research, increased by the functioning lump sum (75% of depreciation charges and 40% of staff costs). The starting point is therefore a record of time by engineer, by project and by type of task, kept continuously. Reconstructing hours from memory at the year end, a few weeks before the tax return is filed, is the scenario that ends badly.
A base that has changed. Three items have left the base: the cost of filing, maintaining and defending patents, technology-watch spending, and the doubling of the base that young doctorate holders used to attract. The functioning lump sum also fell from 43% to 40% of staff costs for expenditure incurred from 15 February 2025. A file rolled forward from one year to the next, without picking up these changes, overstates the credit and manufactures its own reassessment. The credit is declared on form 2069-A-SD, filed with the tax return.
JEI status: a threshold raised to 20%, and a benefit that has changed nature#
The jeune entreprise innovante (JEI) is the French young innovative company status (CGI, article 44 sexies-0 A). It is within reach of many consultancies, provided you reason on the current regime, not the one still described online.
The expenditure condition is now a minimum of 20% of the year's tax-deductible expenses devoted to research. The former threshold of 15% applies only to financial years ended before 1 March 2025. Between 5% and 20% of research and development expenditure, the company falls under the jeune entreprise de croissance (JEC) status, which adds a condition on economic performance indicators. Other conditions: under eight years old (created since 1 January 2023), a European-sense SME (fewer than 250 employees, turnover below €50 million or balance sheet below €43 million), capital at least half held by individuals, no creation by concentration or restructuring.
The benefit has changed nature. The exemption from corporate income tax is abolished for JEI companies created on or after 1 January 2024. What survives, and matters for a BET whose engineer salaries make up most of its costs, is the exemption from employer social security contributions (social insurance and family allowances) on staff assigned to research, within a double cap: 4.5 times the minimum wage per employee (€8,401.58 per month) and 5 times the annual social security ceiling per establishment (€240,300 a year, for a 2026 ceiling of €48,060). This social exemption, like the local business-tax and property-tax exemptions granted by local authorities, stays open to companies created before 31 December 2028: the Finance Act for 2026 extended the creation window to that date. A consultancy incorporated in 2026 is therefore still eligible, contrary to a widespread claim that closed the window at the end of 2025.
The research tax credit and JEI status can be combined: one works on tax, the other on payroll. Documented properly, the combination changes the cash trajectory of a young consultancy.
Fixed-day contracts and the Syntec collective agreement (IDCC 1486)#
Most BETs fall under the Syntec collective agreement (IDCC 1486), and their engineers are often on a forfait annuel en jours, an annual fixed number of working days rather than counted hours. The point specific to a BET: the fixed-day contract removes the need to count hours, not the need to track time spent per project. Two different objects: one from employment law, the other from article 622-5 of the PCG and the credit base. The director who says "my engineers are on fixed-day contracts, so I do not track time" loses both.
Managing margin project by project: the indicators of an engineering consultancy#
The statutory accounts of an engineering consultancy say very little that is useful. Margin is won or lost project by project, on contracts whose drift nobody measures before delivery. The indicators below are the ones we put in place, and they do not exist in a standard chart of accounts.
Common mistakes in the consultancies we take over#
- Invoicing treated as recognition. Revenue follows the invoicing schedule, not real progress: the result becomes an artefact of the negotiation.
- Declarative time sheets, filled in at month end from memory. They validate neither the completion percentage nor the credit base, and do not survive an audit.
- A credit base modelled on the engineering invoiced to the client, booked wholesale as research: the sector's most predictable reassessment.
- A flat rate still taken at 43%, when it has been 40% since 15 February 2025, or a base still holding patent costs and technology watch.
- A Syntec revision clause never activated, or indexed on an index that does not exist.
- Work in progress valued at selling price instead of production cost, which books a margin not yet earned.
How much does an accountant for an engineering firm cost?#
Our fees depend on the structure (sole engineering consultant or company), the volume, and high-value work such as the research tax credit. They are set in the engagement letter, with no surprises.
| Profile | What is covered | Fees |
|---|
| Sole engineering consultant (BNC) | Bookkeeping, 2035 return, VAT, day-to-day advice | from €258 excl. VAT/month |
| Engineering firm (small company) | Bookkeeping, VAT, closings with completion, financial statements and tax return, light payroll | from €350 excl. VAT/month |
| Growing engineering firm | Monthly closings, project margin, Syntec payroll, dashboard | on quotation |
| CIR and JEI eligibility review | Project review, post-2025 Finance Act scope, documentation plan | on quotation |
A costed quotation is sent within 24 working hours after a first conversation.
Our conviction. In an engineering firm, everything hinges on a single discipline: posting time to each engagement. It is what allows percentage-of-completion recognition under French GAAP, what builds a defensible research tax credit base, what makes margin readable project by project. One and the same slackening brings down all three. Our job is not to keep accurate books once a year, it is to install, from the order letter onward, the setup that turns your accounts into a decision tool rather than a late statement of fact.
What Hayot Expertise does for your engineering consultancy#
The firm is led by Samuel Hayot, Expert-Comptable et Commissaire aux comptes (chartered accountant and statutory auditor), registered with the Ordre des experts-comptables of Île-de-France and with the CNCC. Cabinet Hayot Expertise, 58 rue de Monceau, 75008 Paris. A solo firm, no staff: the person you talk to is the person who handles your file.
In concrete terms: project-level cost accounting and time tracking, revenue recognised as contracts progress with the documentation required by article 622-5, TEC and FAE at the year end, a secured CIR and CII base, JEI conditions and the employer contributions exemption, price revision through the Syntec index, plus bookkeeping, tax and payroll.
A first conversation is enough to say, on your documents, whether your open contracts are recognised correctly and whether your time tracking satisfies both the PCG and the tax credit.
Updated 26 August 2026. Informational content reviewed by a chartered accountant registered with the Ordre des experts-comptables of Île-de-France.
Decennial liability: an engineering firm is not always a builder#
The question comes up in nearly every building-sector engineering file, and the answer is not uniform. The presumption of decennial liability under Articles 1792 and following of the French Civil Code falls on builders, and Article 1792-1 counts among them "any architect, contractor, technician or other person bound to the client by a contract for services". Two conditions therefore combine: acting as a technician on the works, and being bound to the client by a contract for services.
What follows in practice: an engineering firm designing a structure, building services or a technical installation under a contract with the client falls within the scope, together with the insurance obligation that comes with it. A firm working as a subcontractor to another builder, with no direct contract with the client, or whose engagement does not bear on the works themselves, does not fall within it in the same way. The distinction is read in the contract, not in the description of the activity, and it drives both the insurance premium and the provisioning of disputes.
Three points that decide an engineering firm's accounts#
Revenue recognition is a choice, and the choice has conditions. French accounting standards let an entity account for long-term contracts either on completion of the contract or as it progresses. Choosing the second requires being able to estimate the outcome at completion reliably, which in turn requires identifying total contract revenue and total attributable costs, and running management tools that validate the percentage of completion and revise the estimates as work advances. That third condition is where most files fail: it does not ask for an intention, it asks for a working system.
The research tax credit base narrowed. The operating-cost lump sum computed on staff costs was reduced from 43% to 40% for expenditure incurred from 15 February 2025, and three items are no longer eligible and have been removed from the tax base: patent filing, maintenance and defence costs, technology watch expenditure, and the doubling of the base formerly granted for young doctorate holders. Those patent costs remain taken into account under the innovation tax credit for small and medium-sized enterprises, within the shared annual cap, for expenditure incurred up to 31 December 2027.
Price revision clauses are written and then forgotten. Engineering contracts commonly carry a revision clause indexed on the Syntec index, and it is often never applied because the reference date and the revision frequency were not settled at signature. On multi-year engagements, that omission absorbs salary inflation straight out of the margin.