If you buy a pure-breed dog, it must in any case be registered in the Livre des Origines (“book of origins”). Breed dogs born in France are registered in the LOF (Livre des Origines Français – the French book of origins). Being a “LOF puppy” means it is of a pure breed, and is registered in the book. The registering certificate, which is only provisional, will give you the dog’s details and its genealogy over 3 generations. You might not have this document the first day, however, since the formalities of registration tend to take some time. But the breeder must give you proof that the dog is actually in the process of being registered in the LOF: he should at least give you a photocopy of the registration request form for the litter.