Outside city walls, inside an inconspicuous warehouse, lies a historical treasure trove - dozens of trains and buses that once served the French capital. This is where the RATP, Paris's transport authority, proudly stores -and restores - over a century of its heritage. From the revolutionary 1900 wooden metro, to the first auto-pilot trains, one of the managers of the site takes AFPTV on a guided tour - just don't call it a museum.