You need a French company's number: to fill in a supplier form, set up a customer account, issue an invoice or check who you're dealing with. French companies have two numbers that people mix up, the SIREN and the SIRET, and the one you need depends on what you're doing. This guide explains the difference in one minute, then shows five free ways to find the right number, all from official sources.
Formats come from service-public.fr (page checked on 3 April 2026); examples were checked on the State's company directory on 10 October 2026.
What you'll learn
- The difference between SIREN and SIRET, and which one you need
- Five free ways to find them
- How to pick the right SIRET when a company has many sites
- What to do when you can't find a company
- How to check the number you found
SIREN or SIRET: which one do you need?
According to service-public.fr:
- The SIREN has 9 digits. It identifies the company itself, the legal unit. A company has one SIREN for its whole life.
- The SIRET has 14 digits: the 9 digits of the SIREN plus 5 digits specific to each establishment (each site where the company operates). A company has as many SIRETs as it has sites, and the head office has its own.
So Renault has one SIREN, 441 639 465, and its head office has the SIRET 441 639 465 00091. Its other sites have other SIRETs that start with the same nine digits.
Which one to use?
- To identify the company (contract, KYB, CRM account, e-invoicing): the SIREN.
- To identify a particular site (a delivery address, a local branch, a payroll establishment): the SIRET of that site.
- When a form asks for "the SIRET" without saying which, it usually means the head office's.
Five free ways to find the number
1. On the company's own documents
The fastest and most reliable source is a document the company produced. According to service-public.fr, invoices between professionals must show the seller's SIREN, and the seller's VAT number. Look at:
- an invoice or a quote;
- its terms of sale;
- the legal notice (mentions légales) on its website;
- its email signature or letterhead.
Copy the number from a document rather than a search result: it's the number the company says it has.
2. In the official directory, by name
The Annuaire des Entreprises is the State's free company directory, built on INSEE's Sirene directory and other official data. Search by name, ideally with the city or postcode. Each result shows the SIREN, the head-office SIRET, the status (active or ceased), the address and the activity.
Be careful with common names. A search for "renault" returns thousands of results, and the first ones named exactly RENAULT aren't the carmaker. Always check the address and the activity before you copy a number. See why AI agents and people get company data wrong.
3. From the VAT number
A French intra-community VAT number is FR, two characters and the SIREN, according to service-public.fr. If you have the VAT number (from an invoice, or VIES), its last nine digits are the SIREN. FR63441639465 gives 441 639 465. See checking a VAT number with VIES.
4. From the RCS number
Companies registered in the trade and companies register show an RCS number, written as "RCS", the city of the registry, and the SIREN. In "RCS", then a city, then 441 639 465, the last nine digits are the SIREN. See the RCS number explained.
5. Ask the company
It sounds obvious, and it's the best option for anything important: ask your contact for the SIREN in writing. It's a normal request in France, and it prevents you from picking the wrong company with a similar name.
Picking the right SIRET
When a company has many sites, the directory lists each establishment with its own SIRET, address and status (active or closed). To pick the right one:
- Start from the address you need: the delivery site, the branch you work with.
- Find the establishment at that address in the company's list.
- Check its status: a closed establishment keeps its SIRET in the directory, but it's no longer in use.
- When in doubt, use the head office's SIRET, and ask.
A closed site doesn't mean a closed company: see how to check whether a French company is still active.
When you can't find the company
- Check the spelling and the legal name. The brand on the shop front often differs from the legal name.
- Search by address or by the manager's name in the directory.
- It may be an individual entrepreneur who opted out of publication. Some sole traders choose not to appear in public data. The business can be real; ask them for their Sirene situation notice. See why some French companies don't appear in public searches.
Check the number you found
A number found is not yet a number confirmed:
- Check its format. According to INSEE, the SIREN's ninth digit is a check digit (Luhn algorithm), and a mistyped number fails it about nine times in ten. See SIREN, SIRET and VAT formats.
- Check that it belongs to the company you mean: same name, same address.
- Check the status: active, not ceased.
Doing it for a whole list
If you need numbers for hundreds of customers or suppliers, the manual route doesn't scale. The State's search API answers the same questions as the directory, for free: see how to check a list of SIRENs with Python.
Fuentio's API will return, for a name or a number, the French company with its SIREN, head-office SIRET, status and address, with the source and the check date. It isn't open yet: join the waitlist below to hear the day it opens.
See what we cover in France and Spain.
Limits. Formats come from service-public.fr (page checked on 3 April 2026) and INSEE; the invoice rule from service-public.fr (page checked on 11 August 2026); examples were checked on 10 October 2026. Some individual entrepreneurs don't appear in public data by choice. Not legal advice.
Frequently asked questions
What's the difference between SIREN and SIRET?
The SIREN (9 digits) identifies the company; the SIRET (14 digits) identifies one of its sites. The SIRET starts with the SIREN.
Where can I find a company's SIRET for free?
On its invoices or website legal notice, or in the Annuaire des Entreprises, the State's free directory.
Can I get the SIREN from a VAT number?
Yes. A French VAT number is FR, two characters, then the SIREN.
Why can't I find a company in the directory?
It may be listed under its legal name, not its brand, or be an individual entrepreneur who chose not to appear in public data.
Sources
- Service-public.fr, a company's identification numbers (page checked on 3 April 2026): entreprendre.service-public.gouv.fr
- Service-public.fr, mandatory invoice mentions (page checked on 11 August 2026): entreprendre.service-public.gouv.fr
- INSEE, definition of the SIREN number: insee.fr
- Annuaire des Entreprises (examples checked on 10 October 2026): annuaire-entreprises.data.gouv.fr