SIREN and SIRET

SIREN and SIRET are the two official numbers France uses to identify businesses. The SIREN is a 9-digit code assigned to a legal entity by INSEE, France's national statistics institute. The SIRET is a 14-digit code (the SIREN plus a 5-digit suffix) that identifies a specific physical establishment of that entity. A company has one SIREN and one SIRET per location.

How it works

Every legal entity registered in France, from a one-person consultancy to a multinational subsidiary, receives a SIREN when it registers with INSEE via the business formalities window. The number is fixed for the life of the entity and never gets reassigned, even after closure. Each place where the entity operates (a headquarters, a warehouse, a branch office) then gets its own SIRET, built from the SIREN plus a five-digit NIC (Numéro Interne de Classement). A company with three retail outlets and one head office will have four SIRETs sharing the same SIREN.

Both numbers appear on nearly every French business document: invoices, contracts, delivery notes, official letterhead, and registration certificates like the "avis de situation" or "extrait Kbis". They are also embedded in Factur-X and other e-invoicing formats as mandatory fields.

Validation is straightforward in principle: check digit length, apply the Luhn algorithm to catch typos, and then query INSEE's Sirene database (or a licensed data provider) to confirm the number is active and matches the company name and address on the document. In practice, documents contain transcription errors, outdated numbers from closed establishments, or numbers copied from the wrong entity in a group structure. Real validation means checking against a live registry, not just checking the format.

Why it matters for document processing

An IDP system that only extracts a SIREN or SIRET as a string, without checking it, is only doing half the job. Format-valid does not mean real. A document AI pipeline handling French invoices, contracts, or KYB checks should treat these numbers as entities to extract with NER or key-value extraction, then verify against INSEE Sirene in a validation step, ideally in the same pass as address and legal name cross-checks.

This matters most in three workflows: e-invoicing compliance (Factur-X and PDP flows require a valid SIRET), KYB onboarding (confirming a counterparty actually exists and is active before opening an account), and contract analysis (catching mismatches between the signatory entity and the invoicing entity). Skipping validation lets fraudulent or defunct entities slip through, and it is a common source of rejected e-invoices when the number doesn't match INSEE's records.

Related terms

• KYB (Know Your Business)
• E-invoicing France
• Named Entity Recognition (NER)
• Validation rules
• Cross-document validation

FAQ

Can a SIREN change over time?

No. INSEE assigns a SIREN when an entity registers and it stays fixed for that entity's entire life, including after it ceases activity. What can change is the SIRET, since establishments can open, close, or move, each event affecting the NIC suffix while the underlying SIREN stays the same.

Is checking the format enough to validate a SIRET?

No. Format checks (length, Luhn digit) only catch typos. A syntactically valid SIRET can belong to a closed business or the wrong entity. Real validation requires querying INSEE's Sirene database to confirm the number is active and matches the name and address on the document.