In France, companies register through a number of institutions, predominantly the local centres de formalités des entreprises, but all companies must eventually be registered with the Trade and Companies Register. Once registered, companies receive a SIREN or SIRET number, which is a unique business identifier.
This information is maintained by Infogreffe. Infogreffe provide a basic overview of company information for free, and bulk download of data for a fee.
A note on identifiers:
- A SIRET number is constituted by the SIREN number, plus the NIC code.
- The SIREN number relates to a business, whereas a SIRET number relates to a specific geographically located establishment which will be owned by a business.
- "A SIREN number is your unique French business identification number. This 9 digit number will be requested by all French administration when dealing with you.. It is a proof that you are a fully registered French business" 
"The SIRET code/number is an INSEE code which allows the geographic identification of any French establishment or business.
The 14-digit number consists of three parts:
- first, the SIREN code of the business (or legal unit or person) that owns the unit represented by the SIRET code,
- second, the NIC (French: Numéro interne de classement), is a sequential four-digit number unique to the establishment,
- and finally, a check digit that verifies the entire SIRET number.
For example, 732 829 320 00074 would refer to the seventh establishment of the business with SIREN number 732 829 320." 
"Registration is administered by local centres de formalités des entreprises ( CFE), which checks your application and submits details to the relevant agencies (for a small fee). The CFE will provide you with a form M0, which is for the creation of a company." 
"Creating a company requires that it is registered with the Trade and Companies Register (RCS)." 
"WHAT SOURCE IS USED FOR INFORMATION AVAILABLE ON THE INFOGREFFE WEBSITE?
Information concerning companies entered on the Trade and Companies Register with Registries of the Commercial Courts is taken directly from public registers held by said registries.
Information concerning companies entered on the Trade and Companies Register with other jurisdictions (district courts with commercial jurisdiction, mixed commercial courts in the overseas departments and territories) is provided by the National Industrial Property Institute (INPI).
Information concerning companies not entered on the Trade and Companies Register is taken from data on the SIRENE listing held by INSEE." 
"WHAT DOCUMENTS ARE AVAILABLE ON THE INFOGREFFE WEBSITE?
Infogreffe makes the following information available to the general public:
• Company search and information form
• Key figures concerning a company
• Implementing tracking (free alert, paid consultation).
• Lists of articles of association and company deeds available.
• Your formalities with online help to be incorporated on the Trade and Companies Register.
View, download, order"