Can I Modify All the Information in My Online Income Tax Return?

If you have already submitted your income tax return online and later discover an error or omission, most of the information can be corrected directly through the online service. In general, you only need to update the amounts entered or select and deselect the relevant boxes as necessary.

Information That Can Be Corrected

You may update:

  • Details relating to your dependents;
  • Reported income;
  • Deductible expenses and charges;
  • Information used to calculate tax reductions and tax credits;
  • Information required for calculating the Real Estate Wealth Tax (IFI);
  • Data included in the social declaration for self-employed individuals.

You may also:

  • Add or remove supplementary tax forms and schedules.

Information That Cannot Be Modified Online

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

  • Civil status information;
  • Family status changes such as marriage, civil partnership (PACS), separation, divorce, or death;
  • The address of a dependent student attached to your household;
  • The designation of a trusted third party;
  • The mailing address used when a representative acts on your behalf (guardianship or curatorship arrangements);
  • Your tax residence address as of January 1, 2026.

How to Correct Non-Modifiable Information

To update your civil status, family situation, or tax residence address as of January 1, 2026, you have two options:

1. Submit a request through your secure online account

Log in to your Public Finances account, open the secure messaging service, select “Write”, then choose “Claim or Dispute” followed by “Income Tax”. Supporting documents can be attached directly to your request.

2. Send a corrective paper return

You may also mail an amended tax return to the Public Finance Center (Individual Tax Department) responsible for your tax affairs. Include an explanatory letter and any supporting documentation, clearly stating that the paper return replaces the original return submitted online.

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