There are two marques of this name. For the earlier brand see Gauthier 1902 The second was built from 1972 to 1980 by the brothers Portal and Jacques Boudet of Villefranche-de-Rouergue.
250cc Sachs 1976 with full fairing, fibreglass bodywork, monoshock suspension, discs front and rear mounted on alloy wheels.
125cc GA Criterium, Randonnée and Quatre Saisons, all with 125cc 6 and 7 speed Sachs engines.
AIM-Gauthier enduro. There appear to have been several versions including 80cc and 250cc, the latter an enduro based on the AIM 250CR.
See also BPS, also built by the Boudet brothers.
Sources: srcf.fr, period advertising and catalogues
Could you tell me where I could purchase parts for my 2 vintage 125
cc french bikes called Gauthier powered by Sachs motors ?