Monthly payroll declaration (DSN) — the French employer's monthly filing
The monthly payroll declaration (DSN) replaces a very large number of separate returns: it lets the employer pay social security contributions and send the social bodies — the collection agency, the agricultural social insurance fund, the employment service, the health insurance fund — the information needed for employees' social cover. It is filed once a month online on net-entreprises.fr: this is the "periodic" declaration. Its date depends on headcount: no later than the 15th of the month following the paid work period for a business with fewer than 50 staff, the 5th for a business with 50 or more. Alongside that monthly filing sit EVENT NOTIFICATIONS — sick leave, accident at work, end of contract — which follow a deadline of their own: the "event notification" must be sent within 5 days of the event.
Up to date for 2026 — verified on September 11, 2026Official procedure, no printed formGuide: about 30 min
Deadlines
- The 15th of the following month — fewer than 50 staff
- The declaration must be filed no later than the 15th of the month following the paid work period.
- The 5th of the following month — 50 or more staff
- The declaration must be filed no later than the 5th of the month following the paid work period, for employers whose pay is given in the same month as the work period. Where pay is given in arrears, the deadline is the 15th.
- 5 days for an event notification
- The "event notification" — sick leave, accident at work, end of contract — must be sent within 5 days of the event.
- April, for the apprenticeship tax balance
- Some annual returns go through one specific filing: the apprenticeship tax balance is reported on the April declaration.
Documents to prepare
- The month's payroll data, produced by your payroll software
- The business's headcount, which sets the 5th or 15th deadline
- Whether pay is given in arrears, which moves employers with 50 or more staff back to the 15th
- The month's events: sick leave, accident at work, end of contract, to be notified within 5 days
- Return to work on the expected date after an absence
- Access to the net-entreprises.fr online service
No form is attached to this procedure: the link leads to the official page that describes it.
What this page gives you
The guide above and the link to the official site. ActioFin does not produce any document for this page: whatever you fill in or file is done on the official medium.
Who this applies to
- Every employer that pays wages, whatever its size
- Businesses with fewer than 50 staff, whose deadline is the 15th of the following month
- Businesses with 50 or more staff, whose deadline is the 5th of the following month
- Businesses with 50 or more staff that pay in arrears, which move to the 15th
- Agents, accountants and payroll providers who file on their clients' behalf
Worked example
Example: Ateliers Vasseur, 52 staff, and Boulangerie Tavernier, 2 staff
Ateliers Vasseur employs 52 people and pays January salaries on 28 January 2026, therefore in the same month as the work period: its January filing must go on 5 February 2026. Boulangerie Tavernier, which employs two people, falls under the 15th: its January filing goes by 15 February at the latest. On 3 February an employee of Ateliers Vasseur is signed off sick: the business cannot wait for the next monthly filing, it sends an event notification within 5 days, and that notification serves as the salary certificate for paying daily sickness allowances. The same mechanism would apply to an accident at work or an end of contract. In April, Ateliers Vasseur adds to its filing the annual report of the apprenticeship tax balance, which it will pay in May. Had Ateliers Vasseur paid in arrears, its monthly deadline would have been the 15th and not the 5th, despite its 52 staff.
How to fill it in, step by step
- Work out your deadline: it depends on headcount — the 15th of the following month below 50 staff, the 5th from 50 staff — and, from 50 staff, on whether pay is given in arrears, which moves the deadline back to the 15th.
- File the periodic declaration once a month, online on net-entreprises.fr, for the previous month's paid work period.
- Feed it from your payroll software: it is payroll that produces the individual data the declaration carries to the social bodies.
- Pay your social security contributions on your own contribution due date, not merely when you file: the declaration both reports and pays, but some very small businesses have chosen to pay their contributions quarterly — their filing stays monthly, their payment does not.
- Send an event notification within 5 days of sick leave, an accident at work or an end of contract — the event notification is separate from the periodic filing and does not wait for the monthly deadline.
- Record the normal return to work on the expected date in the monthly filing, after an absence.
- Carry on the filing the returns that were folded into it: the main part of the apprenticeship tax every month, its balance on the April filing.
- Keep the filing consistent with the documents that flow from it: the payslip, whose details it picks up, and the salary certificate, which the absence notification feeds.
The form, line by line
- Periodic filing
- The monthly declaration, filed once a month on net-entreprises.fr for the paid work period. This is the default regime.
- Event notification
- The complement to the periodic filing: sick leave, accident at work, end of contract. It must be sent within 5 days of the event, without waiting for the monthly deadline.
- The 5th deadline
- For employers with 50 or more staff whose pay is given in the same month as the work period.
- The 15th deadline
- For employers with fewer than 50 staff, AND for employers with 50 or more staff who pay in arrears.
- Receiving bodies
- The social security collection agency, the agricultural social insurance fund, the employment service, the health insurance fund: one filing, several recipients — which is what makes this declaration a replacement rather than an addition.
Good to know
- The declaration replaces a very large number of separate returns: what goes into it stops being reported elsewhere, which is why duties as different as the apprenticeship tax and the salary certificate were folded into it.
- It both REPORTS and PAYS social security contributions: it is not an information-only return.
- The event notification has its own 5-day deadline, independent of the monthly one: sick leave starting on the 3rd cannot wait for the following month's filing.
- Paying in arrears changes the deadline for a business with 50 or more staff: it moves from the 5th to the 15th.
- Ends of contract are among the events to notify, for the employment service's purposes.
- The declaration is the channel that feeds the salary certificate for daily sickness allowances: for employers filing it, most of the details flow automatically from the payroll software.
Common mistakes
- Remembering a single deadline: it is the 15th below 50 staff, the 5th above, and the 15th again above 50 staff where pay is given in arrears.
- Waiting for the monthly filing to notify sick leave, an accident at work or an end of contract: the event notification goes within 5 days.
- Assuming the declaration only reports: it also pays social security contributions.
- Carrying on producing separately a return the declaration has absorbed.
- Reporting the apprenticeship tax balance on a filing other than April's.
- Leaving out the normal return to work on the expected date in the monthly filing after an absence.
- Assuming an agent or accountant who files takes on responsibility for the data: it remains the employer's.
Frequently asked questions
What is the monthly payroll declaration for?
It replaces a very large number of separate returns: it lets the employer pay social security contributions and send the social bodies — the collection agency, the agricultural fund, the employment service, the health insurance fund — the information needed for employees' social cover.
When must it be filed?
Once a month, online on net-entreprises.fr: no later than the 15th of the month following the paid work period for a business with fewer than 50 staff, the 5th for one with 50 or more whose pay is given in the same month as the work period. Where pay is given in arrears, the deadline is the 15th.
What is an event notification?
The complement to the periodic filing for sick leave, accidents at work and ends of contract. The event notification must be sent within 5 days of the event.
Does the declaration also pay?
Yes: it lets the employer pay social security contributions at the same time as sending the information, where payment follows the monthly filing. Some very small businesses have chosen to pay their contributions quarterly: their filing stays monthly, their payment follows their own contribution due date.
Which other duties go through it?
Several, including the apprenticeship tax: its main part is reported monthly, and its balance annually on the April filing.
Go further
Compute the related amounts
Understand this form: the related course
Official sources
- entreprendre.service-public.gouv.fr — Monthly payroll declaration (DSN), online service: replacement of a very large number of returns, payment of contributions and transmission to the social bodies (collection agency, agricultural fund, employment service, health insurance fund), monthly filing on net-entreprises.fr, deadline of the 15th of the following month for businesses with fewer than 50 staff and the 5th for those with 50 or more, and event notifications — sick leave, accident at work, end of contract — to be sent within 5 days of the event — September 11, 2026
- entreprendre.service-public.gouv.fr — Apprenticeship tax, checked 8 June 2026: the main part is reported monthly through the payroll declaration, the balance annually on the April one, and the declaration must be filed on the 5th for employers with 50 or more staff whose pay is given in the same month as the work period, the 15th otherwise — employers with 50 or more staff paying in arrears, employers with fewer than 50 staff — September 11, 2026
- ameli.fr — The salary certificate to provide when an employee is signed off work (article dated 4 November 2024): for employers filing the payroll declaration, the details needed to assess entitlement to daily allowances flow automatically from the payroll software, and the normal return to work on the expected date must be recorded in the monthly filing — September 11, 2026
Guide and document provided for information purposes only; they do not constitute personalised legal or tax advice. Check the recipient organisation's requirements and consult a professional if needed.