Twister, if you've seen that name before, you're one ahead of me--and quite a few people ask me about French guns. (I may not know the answers to their questions, but I do know French.) Interestingly enough, one of my French references shows a Dutreuil from St. Etienne who was a 19th century explorer. St. Etienne isn't that big; likely the same family.
There are several French towns named Vitry, but all with something after it, and not close to what you gave. But it's also a French family name. If it's "le Fils", that would mean the son, sort of like Junior in this country.
