My thanks to Michel Humbert for sending in this document. Michel writes that: This homologation certificate, known in France as 'barree rouge'
because of the red line across the document describes the vehicle that was presented for homologation by the manufacturer, and in a second part certifies that the vehicle with chassis number nnn is totally identical to the vehicle described in part 1. You get this document through the dealer when you buy a new vehicle, but it generally gets lost as it is never requested by the authorities, and specially not when you register a used vehicle.
You probably know that mopeds are not registered in France, so they do not have a number plate, they are in fact just known by their engine
number. Until recently, say less than ten years ago, it was the case as well for the 3 or 4-wheeled mopeds, such as the Mini-Comtesse. The reason why these 'less licence' cars now have a number plate is that the police could not fine the driver or owner in case of parking in a forbiddden place.