At one time I owned a number of best French guns, amongst them was a,12 G,bar action hammer gun marked on the rib;"Gyot A Paris, 12 Rue De Ponthieu, and Gyot on the locks." The gun was serial #2903 [#1 OF PAIR].The gun was in the best London style, with straight stock and profuse engraving.The only proof marks were, "London Black powder,"Not for Ball"[1875-1887 time frame for manufacture].My research on the maker was not very fruitful! I did discover that Gyot was competitor at the Hurlingham, International [London], pigeon shooting copetition held in 1897 were in some categories his guns out performed those of Churchill, Purdey & Holland.
Many of the great French makers of this period ceased to operate, but their names are sometimes found on guns of Belgian origin.