DEFINITION
French company identification numbers. The SIREN (9 digits) identifies a company, and the SIRET (14 digits) each of its establishments. Under the e-invoicing reform, the customer’s SIREN becomes a required field on invoices. Clivio reads the SIRET on the invoices it processes.
How the numbers are built
INSEE, the French statistics office, assigns the SIREN when a business joins the Sirene register, and it never changes. The SIRET adds a five-digit establishment number, the NIC, to the SIREN. Take La Poste: its SIREN is 356 000 000, and the SIRET of its head office is 356 000 000 00048. The French VAT number is built from the SIREN too: FR, a two-digit key, then the SIREN, which gives FR39356000000.
The last digit of a SIREN or SIRET is a check digit, so a one-digit typo can be spotted without looking anything up. Our free SIREN and VAT number checker checks it, works out the VAT number and finds the company in the official directory.
Why they matter for e-invoicing
The e-invoicing directory identifies each business by its SIREN or SIRET and shows the platform where it receives invoices. An address can cover the whole business (the SIREN) or a single establishment, which helps when invoices must reach a given site.
The customer’s SIREN is also one of four new mandatory details on invoices between businesses: required since September 1, 2026 for large and mid-sized companies, and from September 1, 2027 for small businesses and micro-businesses. If your turn comes in 2027, start collecting your customers’ numbers now. Our list of mandatory invoice details in France has the full picture. On the invoices it reads, Clivio picks out the supplier’s SIRET.
Frequently asked questions
Is the SIRET the same as the VAT number?
No. The French VAT number contains the SIREN, not the SIRET: FR, a two-digit key, then the 9-digit SIREN. A company with several establishments has one VAT number but several SIRET numbers.
Does an invoice to a consumer need the customer’s SIREN?
No. The new mandatory detail covers the customer’s SIREN when the customer is a business. An invoice to a private individual shows their name and address.