13th-month pay and year-end bonus in France: contributions and tax (2026)
French law does not require a 13th-month payment (13e mois). It comes from your collective agreement, your contract or a company custom. It carries the same contributions as salary, and income tax withheld at source applies in the month it is paid. If your employer uses the neutral rate, that month can be taxed much harder.
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Where the right comes from
No law requires a 13th month or year-end bonus (prime de fin d'année). Your employer owes it if the collective agreement (convention collective), a company agreement, your contract or a custom (usage: a bonus paid consistently, to everyone, on a fixed basis) provides for it. That text sets the amount, the payment date and the conditions: being employed on a given date, minimum service, reductions for some absences, pro-rating for joining mid-year or part-time work. If you leave before the payment date, you get a pro-rated share only if the text says so. Read the relevant article of your collective agreement on Légifrance, or your contract.
Contributions: treated like salary
The bonus is added to gross pay in the month it is paid and carries all the usual contributions, plus CSG and CRDS. For contributions capped at the social security ceiling (plafond de la sécurité sociale, 4,005 EUR a month in 2026), the ceiling accumulates from January. As long as your year-to-date pay stays under the cumulative ceiling, the bonus is treated like the rest of your salary. If the bonus takes you above it, the part above is charged at the higher Agirc-Arrco band 2 rates (8.64% plus 1.08% instead of 3.15% plus 0.86%), so the net share is a little lower.
Tax at source: why the bonus looks overtaxed
Withholding (prélèvement à la source) applies to the month's taxable net pay, bonus included. With a personalised rate (taux personnalisé), the same percentage applies, so the month's tax rises in proportion to the bonus. With the neutral rate (taux neutre, the default used when your employer has no rate for you or you chose not to share yours), it works differently: the grid applies to the whole month. A bonus pushes the month several steps up the grid, and the entire month is taxed at the higher rate. Nothing is lost: the final tax is settled with your return, and any excess is refunded the following summer.
A worked example, roughly
Someone has 2,500 EUR of taxable net pay a month and receives one extra month in December. Under the 2026 neutral grid (in force since May), a normal month is withheld at 5.3%, or 132.50 EUR. In December the month's taxable net becomes 5,000 EUR, the rate jumps to 15.8%, and 790 EUR is withheld. Tax for the month rises by 657.50 EUR on a 2,500 EUR bonus. With a personalised rate of 5%, it would only go from 125 EUR to 250 EUR. Contributions stay roughly proportional.
What to check on the December payslip
The bonus amount against your agreement or contract (one month of base pay, or another formula); the pro-rata if you joined mid-year, work part-time or were absent; the bonus line sitting in gross pay, before contributions; the withholding rate used, and whether it is the neutral rate when you have a personalised rate on impots.gouv.fr. If the 13th month is split (June and December, for example), check both parts arrive over the year. Payslop checks this for free.
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Questions people ask
Can my employer stop paying the 13th month?
It depends on the source. If it is in your contract, not without your agreement. If it is in the collective agreement, it applies as long as the agreement does. If it comes from a custom, the employer can withdraw it, but must inform each employee and the staff representatives with reasonable notice.
Is the extra tax withheld on my bonus lost?
No. Withholding is only an advance. The final tax is calculated on the whole year with your return, and anything overpaid is refunded the following summer.
Do I get the 13th month if I leave before December?
Only if the text that grants it (collective agreement, company agreement, contract) provides a pro-rata on leaving. If it requires you to be employed on the payment date and says nothing about a pro-rata, you are not entitled.
Related guides
Indicative rules as of October 2026. Not tax or legal advice.