Income tax - How are exceptional income taxed?

Verified 10 April 2025 - Directorate for Legal and Administrative Information (Prime Minister)

You received exceptional revenues in 2024 and you want to avoid a sudden increase in your taxes. To limit the tax increase, you can apply for the quota system.

Income is considered exceptional if it exceeds your usual income and do not renew each year.

For example, the following revenues:

  • Reimbursement of a redemption of retirement quarters (for years of study or incomplete years)
  • Additional bonus received by an employee for exceptional services
  • Allowance of door-step received by an owner
  • One-time lump sum payment replacing a small pension
  • Compensatory allowances of notice or paid leave (e.g. in case of dismissal).

To be considered exceptional, an income must exceed the average taxable income of the previous 3 years.

The comparison applies to the revenues of the tax shelter.

However, some income is considered to be exceptional whatever their amount.

This is particularly the case for the following types of income:

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Allowance for breach of contract of employment (taxable part)

If you received severance pay in 2024 (for example, in the event of dismissal), this income (for its taxable part) is considered to be exceptional, whatever its amount.

Mobility allowance 

If you received a mobility grant in 2024, this income is considered as exceptional, whatever its amount.

Voluntary departure allowance

If you received a voluntary departure bonus in 2024 (for example, in the event of a contractual breakdown), this income is considered to be exceptional, whatever its amount.

Voluntary retirement or retirement allowance

If you received a voluntary retirement or retirement benefit in 2024, this income is considered to be exceptional, whatever its amount.

If you received an exceptional income in 2024, you can request that it be taxed on the quotient system.

The quotient system avoids the progressivity of the tax scale.

It applies in 2 steps:

  1. Add quarter from one-time income to your regular income
  2. Multiply by 4 the corresponding additional tax.

The tax on exceptional income is paid in one go.

The income to be taxed under the quotient system shall not not included in other reported income.

You must enter the total of these revenues as one of the following:

  • Within the framework provided for on page 3 of declaration No 2042 C (line 0XX)
  • On free paper attached to Declaration No 2042.

You must detail the amount and nature of income exceptional to be imposed on the quotient, received by each member of the household.

The 2024 online income tax return starts on April 10, 2025.

The deadline varies depending on whether you are filing on paper or online.

You can use the simulator next to find out the date that concerns you:

Check the deadline for your tax return

Tax returns via Internet is required if your principal residence is equipped with internet access and you are able to file your return online.

Tableau - Deadline for filing your tax return online

Department

Deadline for reporting

01 to 19

Thursday, May 22, 2025 at 11:59 pm

20 to 54 (including 2A and 2B)

Wednesday, May 28, 2025 at 11:59 pm

55 to 974/976

Thursday, June 5, 2025 at 11:59 pm

Non-residents

Thursday, May 22, 2025 at 11:59 pm

2025 Online Income Tax Return for 2024 (Special Space)

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