Tax already comes out of the salary: why a return is still needed

Withholding at source (prélèvement à la source) does not replace the annual tax return (déclaration de revenus), which is compulsory whatever the income. The return is what the tax authorities use to work out the final tax bill, compare it with the amount withheld over the year and set a new withholding rate from September. Where nothing has changed, checking the automatic return (déclaration automatique) may be enough.

What the return does when tax is withheld at source

Topic	What the rules say	Source
Obligation to file	A return is compulsory whatever the income; withholding at source does not change this	service-public F34009
New withholding rate	Updated every September, based on the return filed in the spring	service-public F34009
No return filed	No personal rate can be calculated, so a default rate of 0% to 43% applies	service-public F34009
Balance due (solde)	If the tax due on the return exceeds the year's withholding: up to €300 is collected in one payment in September; above €300, in four instalments from September to December	service-public F34009
Automatic return	No change in circumstances: checking the details is enough; a change: the details are added to or corrected	service-public F34009, F358
Low or no income	The return produces a non-taxation notice (avis de non-imposition) and allows tax credits to be refunded	service-public F358

Why file when tax has already been withheld

Withholding is based on an earlier return

The tax authorities set the withholding rate from the tax return, and the rate changes every September based on the return filed that spring. The return lists all tax withheld at source during the previous year, so the figures can be checked and corrected if necessary. Without a return, no personal rate can be calculated and a default rate (taux par défaut) is used instead: between 0% and 43% on the annual scale, depending on pay.

Settling up: a balance to pay or an overpayment

If the tax calculated from the return is more than the total withheld during the previous year, there is a balance to pay (complément d'impôt, solde). It is shown on the tax notice (avis d'impôt) and taken by direct debit: up to €300 in a single payment in September, and above €300 in four instalments from September to December. Withholding for the current year continues alongside. Among the reasons for such a shortfall, service-public mentions income rising without a change in the rate, and an advance on tax reductions and credits (réductions et crédits d'impôt) that turned out too large. So that a balance can be collected or an overpayment (trop-perçu) refunded, any change of bank account is to be reported before 1 July.

Filing on a low income

A return is filed even when income is low or nil. It is the way to obtain a non-taxation notice (avis de non-imposition), which some benefits require, housing benefit for example, and to have tax credits (crédits d'impôt) refunded, such as the credit for childcare costs.

The automatic return

In 2026, an automatic return (déclaration automatique) is issued when two conditions are met: in 2025, tax was charged only on income already pre-filled by the tax authorities, and no change in circumstances was reported during 2025 (the birth, adoption or fostering of a minor child does not count against this). In the spring, a notice arrives listing the income the authorities have on record. If everything is correct, nothing more is required. If circumstances have changed, for example a new child, a marriage or different income from the year before, the details are added to or corrected.

What can change the answer

• How the return is filed. Filing online is compulsory where the home has internet access and filing online is possible; not doing so incurs a surcharge of 0.2% of the tax due, with a minimum of €60.
• A first return. For a first return by someone who was not included on their parents' return the year before, the rules provide for a paper form (service-public F358). The impots.gouv page "Puis-je déclarer en ligne pour ma première déclaration de revenus ?" also describes an online route: someone who has not received a letter with a tax number gives their details to the tax office and, once checked, creates an online account. The guide on a first return without a tax number covers this in detail.
• Changes in family circumstances. Marriage, PACS, the birth or adoption of a child, the death of a spouse, divorce or the end of a PACS are reported to the tax authorities within 60 days, as they change the withholding rate.
• Timing. The 2026 return, for 2025 income, is closed; the 2027 return, for 2026 income, opens in April 2027.

Who can confirm

Service-public lists the tax information line (service d'information des impôts, 0809 401 401), the local tax office for individuals (service des impôts des particuliers, SIP), secure messaging in the espace Finances publiques, and France Services centres.

About Fiscly

Tax comes out of every month's pay, yet in the spring a request to file a return still arrives, and that is confusing. We went through this ourselves and built Fiscly for ourselves and for others who have moved here.

A questionnaire in six languages that ends with a step-by-step guide to the declaration.

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This material is for general information and does not replace individual advice.