Introduced by the 2022-1616 Social Security Financing Act for 2023 and the decree no. 2023-1384 of December 29, 2023the substitution DSN is the last resort for a non-compliant Déclaration Sociale Nominative (DSN).
But what's involved, what's the roll-out timetable, and how do you prepare?
DSN substitution: what is it?
This is a system for verifying and correcting erroneous DSNs by social security organizations (OPS).
At each monthly deadline, this system provides for the reporting of any anomalies detected via the Comptes Rendus Métiers (CRM) transmitted by the organizations receiving the DSN. Standardized and integrated into payroll software, these CRMs must be followed by corrections. Failing this, the latter are carried out by the organizations, using substitute DSNs.
DSN substitution and deployment schedule
A precise roll-out schedule has been programmed, and here are the main stages:
- From 2024 Each month, collection agencies issue standardized CRMs to employers, notifying them of any anomalies observed in the month declared and to be corrected at the next due date.
- From March 2025 Introduction of CRM reminder for uncorrected anomalies from the previous calendar year (2024). Employer inaction will not be followed by a substitution DSN. It can only be issued in the event of on-site or documentary inspections by the inspectors in charge of collection.
- From March 2026 2025: Receipt of reminder CRMs for the year 2025. This is the generalized implementation of substitution DSNs: anomalies that are proven, not contested or not corrected by the employer will be followed by DSN substitution in May/June 2026 by Urssaf and MSA
DSN substitution: how to anticipate?
Here are a few non-exhaustive best practices to help you get ahead of the game:
- Know where to find the CRMs that are available on payroll software, on net-entreprises.fr and on the portals of certain organizations such as Agirc-Arrco
- Get into the habit of consulting them quickly after each DSN transmitted, to correct any anomalies.
- File them in a dedicated folder for smoother tracking of declarations
- Training teams.
