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Each local authority has a unique identifier, the SIREN number, essential for any administrative procedure, statistical study, or subsidy control. However, finding this nine-digit sequence can sometimes prove challenging, especially when a merger or modification occurs. This guide offers a pragmatic and illustrated approach to accurately locate the SIREN of a town hall, departmental council, or region.
🗂️ What is the SIREN? It is a unique 9-digit code, assigned by INSEE to each authority to identify it in public databases.
🔍 Main sources: consult the INSEE website, explore the data.gouv.fr portal, and check the official journals (JORF).
📋 3-step method: identify the exact name, start your search on INSEE, then cross-check the information with a second source.
⚠️ Tips: beware of merged or overseas authorities: their SIREN numbers change, as does their administrative status.
Sommaire
Why is the SIREN number essential for a local authority?
Definition and scope of the SIREN
The SIREN (Identification System of the Directory of Enterprises) primarily serves to legally identify each public or private entity. Unlike the SIRET, which breaks down the SIREN by establishment, the SIREN remains fixed throughout the life of the structure. In the territorial context, this code distinguishes a municipality from a community of municipalities, a department, or a region within national databases.
Common uses
Local authorities, audit firms, researchers, or suppliers of public goods and services: all benefit from this number. It is notably used to:
- verify the legality of a public contract,
- consult financial and budgetary data,
- conduct territorial statistical studies,
- carry out administrative procedures online.
Where to search for the SIREN number?
The INSEE website
The INSEE search engine is the most reliable starting point. By entering the official name of the authority (without abbreviations), you access a detailed record presenting the SIREN, address, activity code, and even the history of any name changes.
The data.gouv.fr portal
Data.gouv.fr concentrates open datasets, including the Sirene Directory. You can download a CSV file or use an API to query the database: ideal for automating the retrieval of multiple SIREN numbers at once.
Official Publications
The official journals (JORF, Official Bulletins) announce any creation, merger, or dissolution of local authorities. By searching the archives, you can find the date of the act and, generally, the new assigned SIREN number. A quick visit to legifrance.gouv.fr never hurts.
Practical Methodology to Identify a SIREN
Step 1: Identify the Exact Official Name
Before starting any search, make sure of the full wording: “Commune of X”, “Metropolis of Y” or “Region Z”. Abbreviations (M° for Metropolis, CDT for Departmental Council) can lead to zero results or to the identification of another entity.
Step 2: Conduct a Search on INSEE
On insee.fr, simply enter the name in the “Search in the Sirene database” field. If several administrative levels bear the same name (e.g. “Community of communes of Val-de-Marne” vs “Department of Val-de-Marne”), refine with the postal code or region to get it right on the first try.
Step 3: Cross-check with Other Sources
Once the number is obtained, validate it via data.gouv.fr or an excerpt from JORF. This cross-check is particularly useful if the local authority has undergone a recent merger or changes its administrative boundaries.
Special Cases and Tips
Mergers and Structural Changes
When several communes merge, a new SIREN emerges for the merged structure. The old numbers remain archived, often mentioned in the merger decrees. You can find these documents on prefecture websites or via Legifrance, filtering by “prefectoral merger decree”.
Overseas Collectivities
The DOM-TOM also benefit from a SIREN like any mainland local authority. However, their records on INSEE may appear under the heading “Overseas territorial collectivities”. In case of doubt, specify the location or nature (single collectivity, COM status, etc.).
Examples of SIREN Numbers of Local Authorities
| Local Authority | Type | SIREN |
|---|---|---|
| Commune of Lyon | Commune | 213300742 |
| Department of Gironde | Department | 244333057 |
| Region Île-de-France | Region | 243800465 |
| Urban Community of Greater Paris | Intercommunality | 200069330 |
FAQ
How to Verify That a SIREN Is Still Valid?
A SIREN number remains valid as long as the local authority exists. On insee.fr, an “Active Structure” mention appears in the Sirene record. In case of dissolution or merger, the cessation date is clearly indicated.
Can the SIREN Be Used to Obtain Budget Data?
Yes: the SIREN serves as a search key on financial data portals (National Aid Database, Local Finance Observatory). It allows filtering budgets, administrative accounts, and public subsidies.
Is There an Alternative to the SIREN for Identifying Local Authorities?
The INSEE code (5-digit commune code) is sometimes used, but it is not unique for an intercommunality or a department. For the most reliable identification, prefer the SIREN.