France DSN (Déclaration Sociale Nominative)

What it is: The DSN is a single monthly electronic filing, generated directly from payroll, that transmits every French employer’s social and tax data to all the bodies that need it. One file, produced once, routed to dozens of recipients.

Also known as: nominative social declaration, monthly social declaration, NEODeS filing

The problem it was built to solve

Before the DSN, a French employer filed the same employee data repeatedly, in different formats, to different organisations, on different calendars – the DADS-U annually, the DUCS to URSSAF, salary attestations to the health insurance fund for sick pay, employment certificates to the unemployment agency, workforce movement returns to DARES, and more. Each had its own rules and its own failure modes.

The DSN replaced that architecture with a single principle: the payroll run is the declaration. Data is produced once, in a standard format, and distributed.

The legal basis is Article 35 of the Warsmann simplification law of March 2012, with Decree No. 2016-611 setting the phase-in schedule. It has been mandatory for all private-sector employers since January 2017, and for the public sector since January 2022. For the private sector it is now the default and effectively sole channel for the formalities the DADS-U used to cover.

What the single file actually carries

The DSN is nominative – it reports at individual employee level, not in aggregate. Each monthly file carries, for every person on payroll: identity and contract details, gross and net pay, hours, absences, contribution bases, employer and employee contributions, and the income tax withheld at source.

From that single transmission, data flows to URSSAF for social contributions, the Assurance Maladie for sickness and maternity benefits, France Travail for unemployment rights, AGIRC-ARRCO for supplementary pension, the DGFiP for withholding tax, supplementary health and provident insurers, DARES for workforce statistics, and MSA for employers in the agricultural regime. It also feeds individual employee entitlements including the personal training account (CPF) and the professional prevention account (C2P).

Two elements deserve particular attention from international payroll teams:

Withholding tax (prélèvement à la source). Since 2019 the DSN carries the taxable net for each employee and applies the individual withholding rate that the tax authority returns to the employer. The employer does not calculate the rate; it receives it and applies it. If the return is not collected and loaded, the default rate applies – which employees notice immediately.

Montant net social. Mandatory on payslips since 2023 and declared through the DSN, this standardised “net social amount” is the reference figure used by social bodies to assess entitlements such as the activity bonus and RSA. It is a defined calculation, not a derived figure, and getting it wrong has consequences for employees rather than for the employer – which is precisely why it is easy to leave unvalidated.

The monthly rhythm

The DSN is filed every month, whether or not anything changed, through the net-entreprises.fr portal – either by depositing a standards-compliant file (EDI) or transmitting directly from payroll software. Agricultural-regime employers file through MSA channels, with some specific deadlines of their own.

Two deadlines apply:

• The 5th of the following month for employers of 50 or more employees who pay salaries within the same month.
• The 15th of the following month for all other employers.

Where the 5th or 15th falls on a Saturday, Sunday or public holiday, the deadline moves to the next working day. Because the filing is generated from a closed payroll, the operative deadline for the payroll team is several days earlier than the statutory one – a distinction that gets lost in implementation planning more often than it should.

Event signalements: the second filing stream

Alongside the monthly cycle, certain events must be reported as they happen rather than waiting for month end. The main ones are:

• Arrêt de travail – work stoppages for sickness, workplace accident, maternity or paternity, which trigger the employee’s daily benefit entitlement.
• Fin de contrat de travail – any departure, which generates the dematerialised employer certificate for France Travail and opens the employee’s unemployment rights.
• Reprise anticipée – early return to work following a stoppage.
• SADV (signalement d’amorçage des données variables) – used to transmit information affecting employee rights and withholding tax calculation where the normal flow doesn’t cover it.

These must be sent within five working days of the employer becoming aware of the event. Late transmission delays the employee’s benefit payments and generates anomalies downstream. In practice this is the part of the DSN that most often breaks in internationally managed payrolls, because it requires HR to feed payroll continuously rather than at cut-off.

The return channel: CRM and why they matter

Filing is only half the loop. Each receiving organisation sends back a compte rendu métier (CRM) – a report flagging errors or suspected errors in what was submitted. CRMs arrive monthly, and increasingly in standardised form.

Treating CRMs as informational is the single most expensive mistake in DSN management. Uncorrected anomalies accumulate, corrupt employee records at the pension and health funds, and surface years later as entitlement disputes. The self-check tools published alongside the standard – dsn-val in particular – exist so that files can be validated before deposit rather than corrected after.

What changed in 2026

The NEODeS 2026.1 standard (P26V01) took effect for the 2026 filing year. It is a technical evolution rather than a functional overhaul – new reference tables and strengthened controls – but every payroll system must be compatible with it to file validly. Where payroll is run on a global platform with a French localisation, standard-version upgrades belong on the release calendar, not in the support queue.

DSN de substitution. From 2026, URSSAF may correct certain anomalies itself, in place of the employer, where they are not resolved. The consequences are financial and practical at once: retroactive contribution catch-ups, penalties, and a loss of control over what is ultimately reported to social bodies in the employer’s name. The defence is unglamorous – clear CRM anomalies as they arrive, every month, rather than in an annual clean-up.

DPAE via DSN. From January 2026 it became possible to make the pre-hire declaration through a new DSN signalement, initially for a limited population. It is an early step toward folding another standalone formality into the same channel.

Deferrals. Several planned evolutions were pushed to 2027, with a pilot phase at the end of 2026. Roadmap assumptions made in 2025 should be re-checked rather than carried forward.

What non-compliance costs

Penalties are levied automatically and calculated per employee, indexed to the monthly social security ceiling (PMSS):

• Late filing – 1.5% of the PMSS per employee per month or part-month of delay, roughly €58 per employee per month at 2026 values, with a minimum charge per missing declaration.
• Omitted employees – the same rate applies per undeclared employee per month.
• A cap for short delays – where the delay does not exceed five days, the total penalty is capped at 150% of the PMSS per company, around €6,007.50 in 2026. The cap can only be applied once per calendar year.
• Provisional assessment – in the absence of a DSN, URSSAF may assess contributions provisionally from the last known remuneration, increased by 25% for the first missed deadline and by a further 5 points for each consecutive one. Where no remuneration is known, the calculation is based on the PMSS multiplied by the number of known employees, increased by 50%.
• On regularisation – contributions are adjusted, but an 8% surcharge may be applied, plus 0.2% per month of delay where contributions were not settled on time.

A right-to-error provision can relieve certain penalties where the employer corrects anomalies spontaneously and pays the shortfall before formal notice, subject to conditions including a clean compliance record over the preceding period.

Published penalty figures vary between sources because several distinct rules are in play – per-employee, per-declaration and contribution-based. Any figure quoted in employer-facing material should be traced back to the Social Security Code provision rather than to secondary commentary.

FAQs

Who has to file a DSN?

Every employer of salaried staff in France, private and public sector alike. There is no small-employer exemption: a single-employee company files monthly, and a company director treated as a salaried equivalent triggers the obligation on their own.

Do foreign companies with no establishment in France have to file?

Yes. Employers without a French establishment who employ staff subject to French social security are a recognised category with their own registration route, and they file the DSN like any other employer. The registration mechanics differ from those of a domestic entity, so this should be confirmed against current URSSAF guidance for foreign firms before onboarding.

Does a DSN have to be filed in a month with no payroll activity?

Yes. The monthly obligation is continuous for an active registered employer. A “nil” or no-change filing is still a filing, and its absence is treated as a missing declaration rather than as an implied zero.

Can a submitted DSN be corrected?

Yes, and correction is expected rather than exceptional. Anomalies flagged in CRMs are corrected in the following month’s filing, or through specific regularisation mechanisms depending on the nature of the error. What is not acceptable is leaving them open – which is exactly the situation the substitution mechanism now addresses.

How does the DSN relate to withholding tax?

The DSN is the channel for it. Employers report the taxable net and remit the tax withheld through the same monthly filing, applying the individual rate returned by the tax authority. The DSN replaced the separate PASRAU return for populations now inside its scope.

What is the difference between the monthly DSN and a signalement?

The monthly DSN is the periodic filing of the whole payroll. A signalement is an event report sent within five working days of a specific occurrence – a sickness absence, a departure, an early return – because the employee’s rights cannot wait for month end.

What happens if we miss a CRM?

Nothing, immediately – which is the danger. The anomaly persists, the employee’s record at the relevant fund stays wrong, and the employer loses the window in which correction was simple. From 2026 it also raises the prospect of URSSAF correcting the file on the employer’s behalf.

Does the DSN cover everything, so no other social filings are needed?

Almost, but not entirely. The DSN absorbed the large majority of periodic and event-driven social declarations, and continues to absorb more. A small number of specific populations and formalities remain outside its scope, which is why residual channels still exist for exceptional cases.

What this means for internationally run payroll

The DSN is the reason France cannot be treated as a standard European payroll localisation. Three characteristics drive that.

• It is generated, not compiled – the declaration is an output of the payroll engine, so any gap between the payroll system and the French standard becomes a filing failure rather than a reporting inconvenience.
• It is versioned annually – the standard changes every January, and a system that files perfectly in December can fail in February if the release wasn’t applied.
• It is bidirectional – CRMs and withholding-rate returns have to be collected and loaded back into payroll every cycle. A provider that files but does not process returns is doing half the job, and the half it skips is the half that surfaces later.

Mercans runs French payroll on its own platform with in-country specialists, covering URSSAF and AGIRC-ARRCO calculation, collective agreement logic and DSN filing as a single managed process: https://mercans.com/employer-of-record-payroll-peo/france/

For the wider French employment, payroll and benefits framework, see the Mercans France country guide: https://mercans.com/country-intel/france