David,
THis book might come in handy :
http://www.rayrilingarmsbooks.com/cg...cgi/12491.html
You may want to contact Tom Knox, Sr. over at the NAPCA. His web site is at the far bottom of the page. He is quite the French collector :
http://www.napca.net/index.aspx
You might also contact this fellow...he seems to carry French arms...
http://www.antiquefirearms.com/