Dave:
If the rifling is full length then it would be something similar to a cape gun if the barrels are side by side. If the rifling is only for a few inches at the end then from an English perspective it would be a "Murphy" or "Paradox" used for fowl as well as big game at distance out to say 40-50 yards. In the case of the "Paradox" the bores are usually open and the effect of the rifling is minimal. As to the French aspect, I can't say because I've never be a fan of the French.
Kind Regards,
Raimey
rse
