Income tax - What penalties for late filing?
Verified 05 June 2026 - Public Service / Directorate of Legal and Administrative Information (Prime Minister)
If you report your income late, you will have to pay penalties, an increase in your taxes and possibly late interest.
The 2026 2025 income tax return is complete.
If you missed the deadline, you can still complete your tax return.
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The online declaration remains available
You can file your tax return from your personal online space:
Online declaration is no longer available
You can file your tax return using a paper form:
2026 Income Tax Return 2025 (paper)
Who shall I contact
Increase in tax due
If you report your income late, your tax will be increased by 10%.
The mark-up changes to 20% in the event of late submission of the declaration within 30 days of a formal notice of the tax administration.
In some situations, heavier penalties are applied:
- 40% where the declaration has not been lodged within 30 days of receipt of a formal notice
- 80% in case of discovery of a occult activity, without the need for formal notice.
Warning
Penalties for late filing are calculated on the total amount of tax due, without taking into account the installments and levies already paid.
Interest on late payment
Late payment interest is also charged.
They amount to 0.20% of the tax due per month of delay (i.e 2.4% over 1 year).
This interest applies until the last day of the month in which the tax return is filed.
Please note
The basis for calculating default interest is reduced by the payments you have already made (withholding tax, for example).
Who can help me?
Find who can answer your questions in your region
For general information
By phone:
0809,401,401
Monday to Friday from 8:30 am to 7 pm, excluding public holidays.
Free service + price call
To contact the local service managing your file
Tax department (treasury, tax department...))