Sorry for the late response but I doubt French shooters will respond you one day, so better late than never! Yes they can use revolvers! In authentic category service revolver rulings state Webley, W&Scott-Fosbery, Enfields, S&W 1917-38/200 or K38/200 MP, Nagant 1895 and the French 1892, just to name a few. In the more standard category, you can use any type of modern revolver but barrel length must not exceed 6.1", plain & non-adjustable sights, standard grips - and roughly the maximum caliber is 455 WebleyScott - and you can only shoot .38special in a .357...
