The SIREN identifies a legal entity, the SIRET locates an establishment of that entity, and the Sirene directory centralizes all this data. These three elements form the foundation of the business identification system in France, managed by INSEE. Distinguishing their respective roles avoids concrete errors in administrative procedures, billing, and business relationships.
Electronic Invoicing 2026: the SIREN becomes a routing key
Most guides merely explain the composition of the SIREN and SIRET. However, regulatory news requires understanding their operational role beyond simple identification.
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Starting from September 1, 2026, the client’s SIREN will become a mandatory mention for routing electronic invoices. As part of the electronic invoicing reform, the SIREN will serve as the delivery address in the central business directory. The SIRET will still be used, but it will only be involved in routing for multi-establishment clients who have requested receipt at each site.
This reform has a direct consequence: without a valid SIREN in customer databases, certain invoices will no longer be able to be processed. Companies wishing to know everything about Gestion Entreprise will find a complete breakdown of these identifiers and their uses.
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Before the deadline, a cleaning campaign of customer databases is recommended to verify that each SIREN:
- Is present in a dedicated field and usable by billing tools, not buried in a free text field
- Meets the expected format (9 digits, correct Luhn key)
- Corresponds to a company still active in the Sirene directory
SIREN: 9 digits to identify a unique legal entity
The SIREN number (Business Directory Identification System) consists of 9 digits assigned by INSEE upon the creation of the business. It identifies the legal person (company) or the natural person engaged in a professional activity.
The SIREN is permanent. It does not change in the event of relocation of the registered office, modification of activity, or opening of new establishments. It accompanies the company from its registration until its definitive deregistration.
In practice, the SIREN appears on official documents: Kbis extracts, tax declarations, commercial contracts. It is the identity card of the legal entity, regardless of the number of sites where it operates.
SIRET: 14 digits to locate each establishment
The SIRET number (Establishment Directory Identification System) includes the 9 digits of the SIREN plus a 5-digit NIC code (Internal Classification Number). This NIC code identifies a specific establishment, that is, a place where the activity is carried out.
A company has one SIREN but as many SIRET numbers as it has establishments. An artisanal bakery with a production workshop and two sales points has three distinct SIRET numbers, all linked to the same SIREN.
The SIRET changes when the establishment relocates, as the NIC code is tied to the geographical address. The SIREN, however, remains the same. This mechanism explains why some administrative documents sometimes request one or the other: the SIREN is sufficient to identify the company, while the SIRET is necessary when the administration needs to know which site it is addressing.
Sirene Directory: the database that links SIREN and SIRET
The Sirene directory (Computer System for the Directory of Companies and their Establishments) is the national database managed by INSEE. It does not issue the numbers itself, but centralizes information from all companies and establishments registered in France.
The directory covers a broad scope:
- All legal forms (commercial companies, liberal professions, artisans, farmers, associations, local authorities)
- All sectors of activity, without exception
- Entities located in metropolitan France, Corsica, and overseas departments and territories (Guadeloupe, Martinique, Guyana, La Réunion, Mayotte, Saint-Barthélemy, Saint-Martin, Saint-Pierre-and-Miquelon)
The Sirene directory stores three categories of data for each entity: legal information (name, legal form, date of creation), economic information (APE/NAF code describing the main activity), and administrative data (address, history of changes).
Access to Sirene directory data
Since 2017, the data from the Sirene directory has been freely accessible. Anyone can search for a company by its SIREN or SIRET and consult its public information. This openness allows business partners to verify the existence and status of a contact before signing a contract or issuing an invoice.
SIREN, SIRET, and APE code: do not confuse identification and classification
The SIREN identifies the entity, the SIRET locates the establishment, but neither describes the activity carried out. It is the APE code (Principal Activity Exercised), also known as the NAF code, that fulfills this role. Composed of four digits and a letter, it is assigned by INSEE at the same time as the SIREN, based on the declared activity.
The APE code plays a role in determining the applicable collective agreement and is used for economic statistics. It can be modified if the company’s main activity evolves, unlike the SIREN which remains fixed.
On official documents, these three identifiers complement each other: the SIREN indicates “who,” the SIRET indicates “where,” and the APE code indicates “what.” A supplier who checks the consistency of these three elements before entering into a business relationship reduces the risk of dealing with an inactive or poorly identified entity.
The transition to electronic invoicing in September 2026 will reinforce this logic. Routing tools will rely on the SIREN as the primary identifier, the SIRET as geographical precision, and the APE code as a sector classification criterion. Verifying these three data points in your databases now remains the most direct way to anticipate the transition.