My brother, Handsome Paco, was supervising the boxing up of Old Paco's belongings, and made a fascinating discovery. He came across an antique revolver, manufactured in France by Ferdinand Claudin sometime, I believe, in the mid-19th century. Here are some photos (click to enlarge):
There's very little information available on the internet about this gun-making firm, but here is a link to a site that has photos of a rifle, and a revolver that appears to be similar to the one my brother found (scroll down to see the revolver).
Old Paco frequently loaned money to friends and acquaintances, who, almost just as frequently, wound up not being able to pay him back in cash, so he often took payment in "stuff", including the occasional firearm (in fact, that's how I acquired a rare G98/40: a modified Mannlicher rifle manufactured in Hungary during the Nazi German alliance/occupation; it's a bolt-action rifle chambered in 8mm, and it's extraordinarily accurate). I think it's likely that he came by the French revolver in this way. It's pretty rough looking, and I doubt that it's worth very much, so I told my brother he ought to just keep it as a conversation piece.
Update - R-man, in the comments: "I can just picture the 18th century French Gendarme, Dirty Henri, pointing that at a bad guy: Vous sentez-vous chanceux, punk?"