Income Tax: How to Correct Your Online Tax Return Until December 2026

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Have you received your tax assessment notice and noticed an error or omission in your income tax return? The French tax authorities allow taxpayers to amend certain information through an online correction service. For 2026, this service is available from July 29 through December.

Who Can Use the Online Correction Service?

Taxpayers who filed their income tax return electronically, either through the official tax website or the mobile application, can access the online correction service.

Individuals who benefited from the automatic tax return process are also eligible to make corrections.

The service allows taxpayers to amend their 2026 tax return relating to income earned in 2025.

How to Correct an Online Tax Return

Corrections Through Your Personal Tax Account

To update your tax return online:

  1. Log in to your personal tax account using your tax identification number and password.
  2. Access the online correction section.
  3. Modify the information that requires adjustment.
  4. Review and validate the changes.

Information That Can Be Updated

Most financial information can be corrected online, including:

  • Declared income amounts.
  • Deductible expenses and charges.
  • Information used to calculate tax reductions and tax credits.
  • Data relating to the Real Estate Wealth Tax (IFI).
  • Incorrectly selected or unselected boxes on the tax return.

Information That Cannot Be Changed Online

Certain personal details cannot be modified through the online correction service, including:

  • Changes in family status, such as marriage, divorce, civil partnership registration or termination, and death.
  • Civil status information.
  • Tax residence address as of January 1, 2026.
  • Correspondence addresses managed by a legal representative under guardianship or similar arrangements.
  • The address of a dependent student attached to the household.
  • The appointment or modification of a trusted third party.

Correcting a Return Through the Mobile Application

The official tax mobile application also offers a correction service starting on July 29, 2026.

Using the app, taxpayers can modify:

  • Dependents and individuals attached to the tax household.
  • Salaries, wages, pensions, retirement income, and annuities.
  • Investment and movable capital income.
  • Micro-property income.
  • Alimony payments.
  • Certain tax reductions and tax credits, including those related to charitable donations, union dues, childcare expenses, personal services, and educational expenses for dependent children.
  • Bank account details (RIB).

In some situations, the mobile application can also be used to correct tax returns initially filed through the website.

Corrections for EDI Filers

Taxpayers who submitted their tax return using the Electronic Data Interchange (EDI) system must use the dedicated EDI Correction procedure to amend their 2026 return relating to 2025 income.

This requirement also applies to corrections involving the Real Estate Wealth Tax (IFI), where applicable.

What Happens After a Correction Is Submitted?

Once the correction process is completed, a confirmation email is sent to the taxpayer.

As with any tax return, the tax administration may request supporting documents or additional information before validating the changes. In some cases, corrections may be rejected if they are not adequately justified.

After review of the amended return:

  • The tax due is recalculated.
  • The withholding tax rate is updated.
  • A revised tax assessment notice is issued if the corrections are accepted.

Depending on the outcome:

  • If the revised calculation results in a lower tax liability and the balance has already been paid, a refund will be issued after the new assessment notice is generated.
  • If additional tax is due, a new payment deadline will be specified on the updated notice.

What If the Online Correction Period Has Ended?

After the online correction service closes in December 2026, taxpayers can no longer amend their return through the online correction platform.

Any further changes must be requested by filing a formal claim with the French tax administration through the taxpayer’s online account or another authorized procedure.

How to Correct a Paper Tax Return

Taxpayers who submitted a paper tax return cannot use the online correction service.

Instead, they must submit a formal claim within the applicable statutory deadline.

Deadline for Filing a Claim

A claim may be submitted until December 31 of the second year following the year in which the tax was officially assessed.

For example, for tax due on 2025 income and assessed in 2026, the claim deadline is December 31, 2028.

Ways to Submit a Claim

Taxpayers can file a claim through several channels:

  • By using the secure messaging service in their personal online tax account to report an error in the tax calculation.
  • By sending a written request to the relevant public finance office.
  • By visiting the tax office in person.
  • By contacting the office by telephone.

A written claim should generally include:

  • The taxpayer’s full name.
  • Postal address.
  • Signature.
  • Identification of the tax concerned.
  • A detailed explanation of the issue.
  • Supporting documentation that justifies the requested correction.

When certain information cannot be updated online or when online services are no longer available, filing a formal claim remains the official procedure for requesting a correction from the French tax authorities.