I'm glad I found this thread. This past week, I purchased a French Rook rifle on Gunbroker. It was listed as a Mon Marquis and said they could not identify the caliber, even though they had a chamber cast (included). They only had a few pictures. I was the only bidder. I recieved it Thursday and have spent most of the time trying to find information. It is a relatively simple Rook rifle like many of the English side lever single shots, but the wood was very high grade, it had very good quality engraving ( heavy oak leaf around the tang and breech and nice floral encircling the pins and screws. It has a really nice feature in the fore end release. It appears to be attached with a screw and the pivot pin for the barrel has a screw head. I suspected it came apart like a Tell rifle, but when I started to remove the fore end screw, it turned only a quarter and stopped. I pulled on the fore end, and it turned out that the screw was actually a release. The entire gun can be disassembled with a quarter turn. The top of the octagen barrel is engraved:

Mon (on superscript) Marquis Coirier Succr (superscript r) Boulevard Des Iteliene 4 Paris.

As noted in one of the posts, the flamboyant script style made it very hard to read. I Googled every variation of my suspected spelling and was coming up blank. The impossible words were Coirier and Italien. The street appeared to be Halien and the only reference I found to Boulevard Des Heliene was an Impressionist painting entitled "View of Boulevard Des Halien". (I later realized the Gallery had mis-read the artist's title. It was, after all, an Impressionist painting.)A MapQuest search for the address kept jumping to Boulevard Des Italien, so I switched to that, realizing that the "It" looked lik a stylized "H". When I tried that with the correct one of the 8 possible versions of Coirier, I found the pinfire blog entry and this thread. Sometimes it is really hard to find the information you need. I f I had read this first, I would have already known when I saw the gun listing.

My only remorse about the gun is that it was marked 380 on the barrel, but had been lined and rechambered to 32 Long Colt. I plan to order some brass and bullets and try it out.

Not wanting to hi-jack the thread but thought that two guns from the same obscure maker at nearly the same time was an oddity.