French Corporate Income Tax (IS) 2026: Rates, Installments, Filing & Optimization

Corporate income tax (IS — impot sur les societes) is the main tax on company profits in France. It applies to profits earned by companies subject to this regime, at the standard rate of 25% since 1 January 2022.

In 2026, the basic rules remain stable, but certain points deserve particular attention: the exceptional surcharge applicable to large companies, updated installment calculation rules, and optimization strategies around tax credits.

This comprehensive guide, written by the experts at Hayot-expertise.fr, gives you all the keys to mastering your company's IS in 2026: who is affected, how to calculate the taxable base, how to pay installments, how to file the declaration, and how to optimize your tax burden.

Companies Mandatorily Subject to IS

Companies known as "capital companies" are mandatorily subject to IS:

• Societes Anonymes (SA) and Societes par Actions Simplifiees (SAS/SASU);
• Societes a Responsabilite Limitee (SARL) and Entreprises Unipersonnelles a Responsabilite Limitee (EURL);
• Societes en Commandite par Actions (SCA);
• Societes d'exercice liberal (SEL);
• Associations and other legal entities carrying out a profit-making activity.

Companies That Can Opt for IS

Certain structures normally fall under personal income tax (IR) but may opt for IS:

• Partnerships (SNC, civil companies, etc.);
• EURLs whose sole partner is a natural person (option revocable within 5 years);
• Certain recently created companies (IR option for up to 5 years for SAS, SARL).

Good to know: The choice between IS and IR is decisive for the director's tax management. It depends notably on the manager's marginal tax rate, their remuneration policy and their need to retain capital in the company.

Standard Rate: 25%

The standard rate of IS is 25% for fiscal years beginning on or after 1 January 2022. It applies to the portion of taxable profit exceeding 42,500 € for eligible SMEs, and to the entire profit for other companies.

Reduced Rate: 15% for SMEs

SMEs benefit from a reduced rate of 15% on the first 42,500 euros of taxable profit, subject to three cumulative conditions (CGI art. 219 I-b):

1. Annual revenue (HT) is less than 10 million euros;
2. The share capital is fully paid up;
3. The capital is held at at least 75% directly by natural persons (or by companies themselves eligible for the reduced rate).

Calculation example for an SME:

• Taxable profit: 80,000 €
• IS on the first 42,500 euros: 42,500 € × 15% = 6,375 €
• IS on the remaining 37,500 euros: 37,500 € × 25% = 9,375 €
• Total IS: 15,750 € (effective rate of ~19.7%)

Exceptional Surcharge (Large Companies)

Following Article 99 of the 2025 Finance Act, an exceptional IS surcharge was introduced for fiscal years opened in 2024 and 2025 (and potentially extended) for large companies:

• Revenue equal to or exceeding 1 billion euros and below 3 billion: surcharge of 20.6% of IS (effective rate ~30.2%);
• Revenue equal to or exceeding 3 billion euros: surcharge of 41.2% of IS (effective rate ~35.35%).

This temporary surcharge does not apply to SMEs.

From Accounting Result to Taxable Result

The IS taxable base is the taxable profit, calculated from the accounting profit with extra-accounting adjustments:

Taxable profit = Accounting profit + Add-backs – Deductions

Main add-backs (non-deductible expenses):

• Fines and tax penalties;
• Personal luxury expenses (leisure hunting, fishing, pleasure residences not used for business);
• Allocated expenses in fiscal consolidation regimes;
• Non-deductible provisions.

Main deductions (non-taxable income):

• Dividends benefiting from the parent-subsidiary regime (5% expense add-back);
• Capital gains on qualifying shareholdings (0% rate, excluding 12% add-back);
• Spreading of certain capital gains.

Installment Principle

IS is not paid in one lump sum at year-end. For companies whose prior year IS exceeds 3,000 euros, four installments must be paid during the year.

Installment Dates for Companies with a 31 December Year-End

The balance (definitive IS minus installments paid) is due within 3 months and 15 days following year-end (i.e. by 15 April 2027 for a 31/12/2026 year-end).

Important: For large companies (revenue > 250 M€), the 3rd and 4th quarter installments must be calculated on the estimated IS for the current year (not N-1), requiring precise tax forecasting.

Exceptions

• First year of taxation: no installment is due;
• Prior year IS below 3,000 €: no installment required; single payment at balance.

When and How to File?

The IS tax return (form 2065) must be filed within 3 months of year-end:

• 31 December 2025 year-end → filing deadline 15 May 2026 (conventional deadline);
• 30 June 2025 year-end → filing deadline 30 September 2025.

Electronic filing is mandatory for all IS companies, via the impots.gouv.fr portal or by EDI via the accountant.

The 2065 return is accompanied by the fiscal package (liasse fiscale) (forms 2050 to 2059, or simplified regimes), which details the balance sheet, income statement and mandatory fiscal schedules.

Carry-Forward (Carry Forward)

A fiscal loss incurred during a fiscal year can be carried forward indefinitely, but with an annual imputation cap:

• Unlimited imputation up to 1,000,000 euros of taxable profit;
• Beyond that, imputation capped at 50% of profit exceeding 1,000,000 euros.

Example: Taxable profit for year N: 2,500,000 €; available carry-forward loss: 3,000,000 €

• Imputation on the first million: 1,000,000 €
• Imputation on the excess (1,500,000 × 50%): 750,000 €
• Total imputed: 1,750,000 € → Residual taxable profit: 750,000 €

Carry-Back

The company may also carry back a loss against the profit of the preceding fiscal year, up to a limit of 1,000,000 euros. This generates a tax receivable refundable after 5 years (or immediately in the event of liquidation, collective proceedings, etc.).

Research Tax Credit (CIR)

The CIR is France's main innovation support mechanism:

• 30% of eligible expenses up to 100 million euros;
• 5% beyond 100 million euros.

Eligible expenses include researchers' salaries, operating expenses (flat rate: 43% of salaries), depreciation of R&D equipment, and costs subcontracted to approved organizations.

Other Notable Mechanisms

• Innovation Tax Credit (CII): 20% (or 40% for companies with fewer than 250 employees) of innovation expenses outside R&D;
• IS reduction for corporate philanthropy (mecenat): 60% of donations to general-interest associations (up to 20,000 € or 0.5% of revenue);
• Director Training Tax Credit;
• IP Box (Patent box): reduced 10% rate on income derived from certain intellectual property assets.

• Standard rate: 25%; reduced rate: 15% for SMEs on the first 42,500 € of profit;
• Four quarterly installments are due if prior year IS exceeds 3,000 €;
• The form 2065 declaration must be filed within 3 months of year-end;
• Fiscal losses are indefinitely carry-forwardable (but subject to an annual cap);
• The CIR is a major tax optimization lever for innovative companies.

(Sources: impots.gouv.fr IS, BOFiP IS, Service-Public.fr, Legifrance CGI art. 205 to 220)