SIREN vs SIRET vs NIC: what is the difference?

The three numbers in short

SIREN stands for Système d'identification du répertoire des entreprises, SIRET for Système d'identification du répertoire des établissements, and NIC for Numéro interne de classement. The first two are issued automatically at registration, with no formalities, as the Service-Public page “How to obtain a Siren or Siret number?” (in French) explains. The SIREN and the SIRET each carry a check digit that catches typing mistakes.

Company, head office and establishments

The company is the legal entity (a company, an association) or the natural person (a sole trader) that carries out the activity. It signs the contracts, receives the invoices and can be the subject of insolvency proceedings. It has a SIREN.

An establishment is a place where the company operates: head office, shop, factory, branch, warehouse. Each establishment has its SIRET. Among them, the head office is the establishment holding the company's official address; it is usually the one shown on the Kbis.

A craftsperson working from home has one SIREN and a single SIRET. A national chain may have one SIREN and hundreds of SIRET numbers, one per shop. A company that closes a site keeps its SIREN; the closed establishment keeps its SIRET, with a closed status.

When the SIRET changes, and the SIREN does not

The SIRET changes whenever the address of an establishment changes: a move creates a new establishment, with a new NIC, and the old one is closed. The SIREN does not change. In practice, a SIRET recorded a few years ago can designate a closed establishment while the company is perfectly active.

This is the classic error in a supplier file: the SIRET of an old address is still there, and an "active SIRET" check fails although the supplier exists. Before concluding that a company has closed, check the status of the company (the SIREN), not only that of the establishment.

Where to find the SIREN and the SIRET

The SIREN appears on the Kbis extract, invoices, quotes and the legal notice of the company's website, and in its VAT number (see What is a SIREN number and how to find it). The SIRET is less visible: it appears on documents tied to a specific site, such as a payslip, which shows the SIRET of the employing establishment, or an invoice issued from a branch. The Kbis usually gives the head office address, not the list of establishments.

If you only have a SIRET, you also know the SIREN: it is its first 9 digits. The reverse is not true. From a SIREN, you must consult the list of the company's establishments to find the one you want, using its address and status.

Which number to use, and when?

• Identifying a customer or a supplier (contract, customer record, credit check): the SIREN, because the company is the party that commits.
• Invoicing: the seller's SIREN and, since 1 September 2026, the customer's are mandatory mentions. The SIRET can also pinpoint the establishment receiving the electronic invoice (see France e-invoicing 2026).
• Delivering to or working on a site: the SIRET of the establishment concerned, with its address.
• Declaring employees or a local activity: social declarations are made per establishment, so with the SIRET.
• Building the VAT number: it is based on the SIREN, never on the SIRET (see French VAT number).

When in doubt, record both: the SIREN for the company, the SIRET for the site you work with. The first 9 digits of the SIRET must then be exactly the SIREN.

With Companies: the company and its establishments

The company record (GET /v2/companies/FR-552100554) gives the company's name, status, legal form, activity and dates. Its establishments are read page by page with the /establishments route:

curl "https://companies.jsonpage.com/v2/companies/FR-552100554/establishments?limit=20" \
  -H "X-API-Key: $COMPANIES_API_KEY"

Each establishment contains its SIRET (registry_id), its name, head_office (true for the head office), its status, its activity, its opening date and its address. The include=establishments block adds the first 20 directly to the company record.

For a form, GET /v2/validate checks in one call that the SIRET entered is well formed, that it exists, that the establishment is active and that it belongs to the company indicated. If the SIRET belongs to another company, the identifiers_match check fails and the response says which one. In Belgium, establishment units (10 digits starting with 2) are read with the same route.

Keep reading

• E-INVOICINGFrance e-invoicing 2026: why your customers' SIREN becomes mandatoryThe four new mandatory mentions, the 2026-2027 timeline and how to verify your customers' SIREN numbers.
• SIRENWhat is a SIREN number and how to find itThe 9-digit format, who gets one, where it appears and how to find a company's SIREN from its name.
• VATFrench VAT number: format and how to check itThe French, Belgian and Swiss formats, the mentions on the invoice and the check before invoicing.