Taxes

From 1 August to 30 Nov 2026

2026 tax return: how to correct it?

Publié le 03 juin 2026 - Entreprendre Public Service / Directorate of Legal and Administrative Information (Prime Minister)

You think you made a mistake on your 2026 tax return, or forgot to declare an amount? You have the option to correct your return, whether you have made it via a paper form or online. Explanations with Public Service.

Add to my calendarIllustration

You made a statement online

Correction after receiving your tax notice

Your tax notice will be available in your Personal area between July 24 and July 31, 2026. If you notice an error on this notice, an online correction service is available in your Public Finance area (function « Access the correction online ») from early august to late november 2026.

During this period, you will be able to access your return and modify amounts or boxes that have been checked. You will then receive a confirmation email. A new tax notice will be issued after the corrective return is processed and your withholding tax rate will be recalculated.

Once the online correction period is closed

You will have to file a complaint on your Private Space. This must be done within a limited time. Consult the sheet of Public Service to find out the deadlines for the various tax claims: Tax claims and legal remedies.

Please note

Some information cannot be corrected via the online correction service:

  • changes in family status (marriage, Civil partnerships, breakdown of Civil partnerships, divorce, death);
  • the updating of civil status;
  • the modification of the designation of a trusted third party, the change of address, the addition or modification of the student's address.

You made a paper statement

You can file a claim after receiving your tax notice:

  • online from the secure messaging service in your Public Finance area, click on the « Write » tab > Claim/Challenge/Income Tax;
  • by mail to your public finance center indicating this information: name, surname and address; tax number; handwritten signature; tax concerned; reason for the complaint with the supporting documents.

Reminder

If you have made an error in a declaration to the administration, you benefit from right to error. It allows you to regularize your error without a penalty being applied.

Additional topics

Une remarque ?