Understanding the C3S Taxe: A Complete 2027 Guide for Companies
Updated: September 16, 2026 – Urssaf / Net-entreprises
What Is the C3S Taxe in France?
The Contribution Sociale de Solidarité des Sociétés (C3S) is a French social contribution imposed on certain companies and businesses based on their turnover.
The C3S is generally applicable when a company achieves more than €19 million in annual turnover excluding VAT, subject to the specific rules for determining the contribution base and applicable deductions.
The contribution is collected and controlled by Urssaf Provence-Alpes-Côte d’Azur and contributes to the financing of the French social security system, particularly old-age insurance and retirement schemes.
For international businesses operating in France, understanding the C3S is important because the contribution is separate from corporate income tax, VAT and ordinary employer social contributions.
Who Must Pay the C3S?
A company or legal entity is required to declare the C3S when both of the following conditions are met:
- the company exists on January 1 of the year for which the C3S is due;
- its turnover excluding VAT exceeds €19 million.
If the turnover does not exceed the €19 million threshold, the company is generally not required to file a C3S declaration.
For example, the 2026 C3S declaration concerns the company’s relevant turnover for 2025. Net-entreprises confirms that companies whose 2025 turnover exceeded €19 million excluding VAT had to declare and pay the 2026 C3S by May 15, 2026.
What Is the C3S Threshold in 2026?
The C3S threshold remains:
€19,000,000 excluding VAT
This is an important distinction: the €19 million figure is not simply a tax-free threshold applied to the entire contribution base.
The C3S system incorporates a €19 million allowance, meaning that the contribution is calculated on the eligible turnover after application of the statutory allowance and any applicable deductions.
Consequently, a company with €20 million of eligible turnover does not simply pay 0.16% on the entire €20 million.
What Is the C3S Rate in 2026?
The C3S rate remains:
0.16%
The rate applies to the contribution base determined under the Social Security Code after taking into account the applicable €19 million allowance and eligible deductions.
Simple example
Suppose a company has eligible turnover of:
€20,000,000
After the €19,000,000 allowance:
€20,000,000 − €19,000,000 = €1,000,000
At a rate of 0.16%:
€1,000,000 × 0.16% = €1,600
This is a simplified illustration. The actual C3S calculation may require adjustments and deductions depending on the company’s activities and turnover composition.
How Is the C3S Taxe Calculated?
The C3S is based on turnover determined according to specific rules under the Social Security Code.
The starting point is generally the company’s turnover excluding VAT and similar taxes, with certain amounts excluded or deducted according to the applicable provisions.
The calculation therefore cannot always be reduced to:
Total accounting turnover × 0.16%
The company must identify the turnover falling within the C3S calculation rules and then apply the statutory allowance and any applicable deductions.
The relevant rules are contained in Articles L.137-30 to L.137-39 and D.137-30 to D.137-36 of the French Social Security Code.
What Turnover Is Included in the C3S Calculation?
The C3S calculation is based on turnover that falls within the scope defined by the Social Security Code.
The turnover is generally considered excluding VAT and certain taxes assimilated to VAT.
Certain taxes and amounts expressly excluded by the legislation must therefore not simply be added to the C3S base.
This is particularly important for companies with complex activities, multiple revenue streams or significant intra-group transactions.
For a large company, the accounting turnover shown in the annual accounts should therefore not automatically be treated as the final C3S contribution base.
When Must the C3S Be Declared?
The C3S is declared and paid during the year following the year in which the relevant turnover was achieved.
For example:
| Turnover year | C3S declaration year | Deadline |
|---|---|---|
| 2025 | 2026 | May 15, 2026 |
| 2026 | 2027 | May 15, 2027 |
| 2027 | 2028 | May 15, 2028 |
The current Urssaf guidance confirms that the declaration and payment must be completed online no later than May 15.
How Do You Declare the C3S Taxe?
The C3S declaration is completed electronically through:
net-entreprises.fr
For the 2026 campaign, the C3S declaration service opened at the beginning of March 2026.
Companies subject to the contribution should therefore make sure that:
- they have access to their net-entreprises.fr account;
- the C3S service is available in their account;
- their company information is correct;
- the turnover figures used for the declaration have been checked;
- the bank details required for payment are up to date;
- the declaration is submitted before the May 15 deadline.
How Is the C3S Paid?
C3S payment is made exclusively by electronic payment (télérèglement) through the company’s net-entreprises.fr account.
The company can manage its bank details and associated SEPA mandates through the C3S declaration dashboard.
An important point is that validating a SEPA mandate does not itself constitute payment.
The company must explicitly initiate the electronic payment after submitting the declaration.
The payment order is then executed on the official C3S due date.
What Happens to an Unused SEPA Mandate?
A C3S SEPA mandate can become invalid if it has not been used for a sufficiently long period.
Urssaf specifies that a mandate for which no SEPA direct debit has been presented for 36 months from the date of the last SEPA debit becomes obsolete and should no longer be used.
Companies should therefore check their banking information and mandate status before submitting their C3S payment.
What Happens If a Company Does Not Declare the C3S?
Failure to submit the required declaration can have financial consequences.
If the company does not declare its turnover, the C3S management body may determine the turnover itself using information available to it, including information derived from publicly available annual accounts.
Failure to comply with the applicable declaration and payment requirements can also result in penalties and increases.
For this reason, companies approaching or exceeding the €19 million threshold should not wait until the deadline to determine whether they are liable.
What Happens During a C3S Audit?
The C3S operates under a declarative system.
Companies calculate and declare the contribution themselves based on their relevant turnover.
In return, Urssaf Provence-Alpes-Côte d’Azur may conduct checks to verify the accuracy of the declaration.
The C3S control is primarily a documentary review, which can be conducted through postal and electronic correspondence.
The company may therefore be required to provide documents supporting:
- turnover figures;
- deductions;
- adjustments;
- legal changes;
- corporate restructuring;
- other elements used to calculate the contribution.
What Happens in the Event of a Merger, Acquisition or Liquidation?
Corporate changes can affect C3S reporting obligations.
Specific procedures may apply when a company undergoes events such as:
- merger;
- absorption;
- change of legal form;
- restructuring;
- safeguard proceedings;
- liquidation;
- other significant changes affecting the company’s legal or economic situation.
Urssaf specifically advises companies undergoing such changes to consult the C3S notice because special declaration procedures may apply.
This is particularly important when a group restructures several entities around the end of a financial year.
Are Small and Medium-Sized Companies Subject to C3S?
Most small and medium-sized companies are outside the C3S system because their turnover does not exceed the €19 million threshold.
The C3S is therefore primarily relevant to companies with substantial turnover.
However, a company approaching the threshold should monitor its turnover carefully because exceeding €19 million can create a declaration and payment obligation for the following year.
Is the C3S the Same as Corporate Income Tax?
No.
The C3S is not the same as French corporate income tax (Impôt sur les sociétés or IS).
These are separate obligations.
| Tax/contribution | Main basis |
|---|---|
| C3S | Eligible turnover |
| Corporate income tax | Taxable profit |
| VAT | Taxable transactions |
| Employer social contributions | Employee remuneration and other relevant bases |
| Local business taxes | Depending on the applicable local tax regime |
A company can therefore be subject to corporate income tax and C3S at the same time.
Is the C3S the Same as VAT?
No.
The C3S and VAT have completely different purposes.
VAT is generally collected from customers and subsequently paid to the French tax administration after deduction of eligible input VAT.
The C3S is a company-funded social contribution based on turnover.
The fact that a transaction is subject to VAT does not mean that the company is simply paying C3S on the VAT-inclusive amount. C3S calculations are made using the specific turnover rules provided by the Social Security Code.
Why Is the C3S Important for International Companies in France?
International groups operating in France may overlook the C3S because it is not administered in the same way as ordinary business taxes.
A foreign-owned French subsidiary can nevertheless be subject to the C3S if it meets the applicable conditions.
This is particularly relevant for:
- French subsidiaries of international groups;
- large retail businesses;
- industrial companies;
- technology companies;
- large service companies;
- companies undergoing mergers or acquisitions;
- groups restructuring their French operations.
The €19 million threshold should therefore be monitored at the level of each relevant legal entity according to the applicable rules.
C3S Taxe 2026: Example of a Company Above the Threshold
Consider a French company that generated:
2025 turnover excluding VAT: €25,000,000
Assuming, for illustration, that the full amount is included in the C3S calculation and no additional deduction applies:
€25,000,000 − €19,000,000 = €6,000,000
C3S:
€6,000,000 × 0.16% = €9,600
The company would therefore have a simplified C3S liability of €9,600.
The actual calculation should always be checked against the detailed C3S rules because certain turnover components and statutory deductions may affect the final taxable base.
What Should Companies Do Before the May 15 Deadline?
Companies potentially liable for C3S should prepare their declaration in advance.
A practical checklist includes:
- Confirm whether the company existed on January 1 of the relevant year.
- Review the previous year’s turnover excluding VAT.
- Determine whether the €19 million threshold is exceeded.
- Identify turnover subject to the C3S calculation rules.
- Check applicable deductions.
- Calculate the contribution at 0.16%.
- Verify the company’s net-entreprises.fr access.
- Check bank details and SEPA mandate information.
- Submit the declaration.
- Explicitly initiate the télérèglement.
- Keep supporting accounting documentation.
C3S Taxe 2026: Key Facts to Remember
The essential figures and deadlines are:
- C3S threshold: €19 million excluding VAT;
- C3S rate: 0.16%;
- 2026 declaration: based on relevant 2025 turnover;
- Declaration and payment: online through net-entreprises.fr;
- 2026 deadline: May 15, 2026;
- Payment method: electronic payment/télérèglement;
- Collection and control: Urssaf Provence-Alpes-Côte d’Azur;
- Purpose: contribution to the financing of social security, particularly retirement insurance.
C3S Taxe FAQ
What is the C3S taxe?
The C3S, or Contribution Sociale de Solidarité des Sociétés, is a French social contribution based primarily on the turnover of companies exceeding the applicable €19 million threshold.
What is the C3S rate in 2026?
The C3S rate is 0.16% of the contribution base after the applicable allowance and deductions.
What is the C3S threshold?
The relevant turnover threshold is €19 million excluding VAT.
When is the C3S due?
The C3S is declared and paid in the year following the year in which the relevant turnover was generated. The deadline is generally May 15.
How do you pay the C3S?
The payment must be made electronically through net-entreprises.fr, using the C3S télérèglement system.
Who collects the C3S?
The C3S is collected and controlled by Urssaf Provence-Alpes-Côte d’Azur.
Does every company have to file a C3S declaration?
No. Companies that do not meet the applicable conditions, including the €19 million turnover threshold, generally do not have to submit a C3S declaration.
Is C3S an income tax?
No. C3S is a social contribution calculated primarily by reference to turnover, rather than taxable profit.
How ESCEC International Can Help With French C3S Compliance
For companies operating in France, C3S is one of several obligations that can arise once turnover reaches a significant level.
ESCEC International can assist international businesses with French accounting, tax compliance and the analysis of their obligations, including situations involving complex turnover structures, corporate reorganizations or international group operations.
For businesses approaching the €19 million C3S threshold, preparing the calculation and reviewing the relevant turnover categories before the filing deadline can help reduce the risk of errors and late compliance.
