The purchase declaration (déclaration d'achat) for motor traders

The purchase declaration (déclaration d'achat) applies exclusively to motor trade professionals in France.
When you buy a vehicle with the intention of reselling it, and your registered business activity includes "purchase and sale of vehicles", you do not put the registration certificate (carte grise) in your own name. Instead, you file a purchase declaration, which must be recorded in the SIV (Système d'Immatriculation des Véhicules — the French vehicle registration system).
When the vehicle is resold, the trader must hand the new buyer the crossed-out registration certificate, a completed and stamped transfer certificate (certificat de cession) — and the purchase declaration.
Without that purchase declaration, the new owner cannot apply for a registration certificate in their own name and will find themselves stuck.
To file the declaration, you send the following to a service accredited by the French state:
– the transfer certificate (certificat de cession),
– a copy of the registration certificate,
– a Kbis extract (the company registration document — required the first time, and to be renewed once it is more than 6 months old),
– the manager's valid national identity card.
On receipt of these documents, the service sends you a purchase declaration receipt (récépissé de déclaration d'achat). You will need to give a copy of this receipt to the future buyer, together with the transfer certificate, the stamped and crossed-out registration certificate, and a roadworthiness test (contrôle technique) less than 6 months old.
In short, the purchase declaration is mandatory for every motor trade professional in France: it must be filed when the vehicle is bought, and it must always be passed on to the new buyer.