How to Check a French Company's Registered Address and Its Establishments (SIRET)

An invoice arrives from a French supplier with an address you don't recognise. A new customer gives you a SIRET instead of a SIREN. A delivery address doesn't match the company's head office. All three are the same question: where is this French company, and is the address you have really one of its own?

France makes the answer public. This guide explains the difference between a company and its establishments, where to check each one for free, how to tell a real address from a shared one, and how to automate the check with one API call.

What you'll learn

• The difference between SIREN (the company) and SIRET (each establishment)
• Where to see a company's registered office and all its establishments for free
• How to validate an address against the official national address base
• What "many companies at the same address" means, and doesn't mean
• How to automate the check

Company or establishment: SIREN vs SIRET

In France, every company has a SIREN, a 9-digit number from INSEE that identifies the legal entity. Each place where it operates (the head office, a shop, a warehouse, a branch) is an establishment with its own SIRET: 14 digits, the SIREN followed by a 5-digit establishment number (the NIC).

So a company with ten sites has one SIREN and ten SIRETs. The siège (head office, or registered office) is one of those establishments.

Two practical consequences:

1. An address can be right without being the head office. An invoice from a branch carries the branch's address. Check that it is one of the company's establishments, not just any address.
2. An establishment can close while the company stays active. A shop that has shut has a "closed" establishment; the company itself may be perfectly active. Check both levels.

For the number formats and their check digits, see SIREN, SIRET and VAT number formats. To find the numbers from a name, see how to find a French company's SIREN or SIRET.

Where to check for free

The State's company directory, the Annuaire des Entreprises, shows for each company its registered office and the list of its establishments, each with its SIRET, address and status (active or closed). Search by SIREN for the company, or by SIRET for a precise establishment.

That answers the first question: is the address on your invoice the head office, another active establishment, a closed one, or none of them?

Is the address real? Checking against the national address base

France publishes an official address database, the Base Adresse Nationale (BAN), maintained with the IGN. Matching a company's address against it tells you whether the address exists as a precise location (down to the house number) or only approximately (the street, the town).

Fuentio's address check does exactly that for a company's registered address, for 1 unit:

curl https://api.fuentio.com/v1/companies/FR/441639465/address -H "X-API-Key: YOUR_API_KEY"

A real answer for RENAULT, recorded on 13 October 2026 (some fields left out):

{
  "data": {
    "original": { "original": "122 B AVENUE DU GENERAL LECLERC 92100 BOULOGNE-BILLANCOURT", "postal_code": "92100" },
    "checked_at": "2026-10-13T16:28:26.126412+00:00",
    "validated": true,
    "confidence": 0.79,
    "precision": "housenumber",
    "normalized": "122bis Avenue du Général Leclerc 92100 Boulogne-Billancourt",
    "municipality_code": "92012",
    "coordinates": { "lon": 2.231934, "lat": 48.830205 },
    "attribution": "Source: Base Adresse Nationale (IGN, API Adresse)",
    "same_address": {
      "active_companies": 38,
      "note": "Active companies Fuentio holds with the same postal code and street line, this one included. Many companies at one address can be a business centre or a domiciliation service."
    }
  }
}

How to read it:

• validated is true only when the best match in the BAN has the record's postal code and a score of at least 0.6. A false means the address couldn't be matched reliably: worth a look, not proof of anything.
• precision says how exact the match is: housenumber is a precise location; a street- or town-level match is vaguer.
• normalized is the official form of the address: useful to clean your own records.
• coordinates place it on a map, for delivery or field checks.

Many companies at one address: what it means

same_address.active_companies counts the active companies Fuentio holds at the same postal code and street line. A high number is common and legal: business centres, shared office buildings and domiciliation services (companies that provide a registered address to others) host many companies at once. Even RENAULT's registered address counts 38: the number is context, not a verdict.

What it does tell you: the address alone says little about where the company actually works. If a supplier you've never met is registered at a domiciliation address and asks for a large prepayment, ask for an operating address too. If your onboarding relies on "we visited the premises", the registered address may not be where you'd go.

A simple routine

Automating it

For one company, the Annuaire des Entreprises is enough. For hundreds, automate:

• GET /v1/companies/FR/{siren} returns the company's status and registered address, with the source and check date (1 unit). The identifier can also be a SIRET.
• GET /v1/companies/FR/{siren}/address validates that address against the BAN (1 unit).
• POST /v1/verifications runs a set of checks at once, including "registered address published", and returns a proof code (5 units): see verify a company and get a proof code via API.

No code yet? The free check shows a company's registered address with its source (3 a day), and the free list check does it for up to 20 companies. In an AI agent, the address check is the check_address tool over MCP. A free API key gives 100 units a month. See what we cover.

Cleaning your supplier master data

The same checks help keep your own records right. Three quick wins: store the SIREN for every French supplier, not only the SIRET of the site that invoices you, so you can always find the company; replace free-typed addresses with the normalized form from the address check, so duplicates become visible; and keep the check date next to the address, so you know when it was last confirmed. When a supplier tells you it has moved, update the address only after the registered office has changed in the official record, and run the address check again.

Limits. The address check covers French registered addresses; Spain isn't available. A validated address exists in the national base; it doesn't prove the company works there. The count of companies at the same address covers the active companies Fuentio holds, matched on postal code and street line. Fuentio returns the registered office, not the full list of a company's establishments: use the Annuaire des Entreprises for that. Example recorded on 13 October 2026.

Frequently asked questions

What is the difference between a SIREN and a SIRET?

The SIREN (9 digits) identifies the company. The SIRET (14 digits: the SIREN plus a 5-digit establishment number) identifies each of its sites, including the head office.

How do I see all of a French company's establishments?

Open the company on the Annuaire des Entreprises: it lists every establishment with its SIRET, address and status.

Can a company be active while one of its establishments is closed?

Yes. Each establishment has its own status. Closing a shop doesn't close the company.

Is a domiciliation address a warning sign?

Not in itself: domiciliation is legal and common. It only means the registered address says little about where the company actually operates.

Sources

• Service-public.fr, SIREN and SIRET numbers: entreprendre.service-public.gouv.fr
• Annuaire des Entreprises: annuaire-entreprises.data.gouv.fr
• Base Adresse Nationale: adresse.data.gouv.fr
• The example answer: RENAULT's address check, recorded from the API on 13 October 2026 (site/data/api-examples in the website repository)