franc:
I'll make a stab at it since you asked. I haven't found the patent but it seems that possibly in the early 1870s Auguste Francotte designed a underlug lock-up with the sidelever. I don't know that he had a satellite office in Paris but Auguste Francotte may have had an agent there like with J. Piddington in England. Lefaucheux and Auguste Francotte were pen pals at the very least and it seems that like Bastin, Francotte was developing lockup systems based, sometimes loosely, on Casmir Lefaucheux's design( interesting Fox reference - 1904 - http://books.google.com/books?id=5o4MAAA...gun&f=false . It appears that Benjamin Kittredge & Company of Cincinnati, Ohio imported similar longarms and A&F may have also but I don't recall exactly when A&F began importing, but I'll look. My opinion is that the number on the top rib is some sort of Brevete number attributing the patent to Auguste Francotte. So if he may the longarm why would he advertise the lockup as his??? It may have been that the lockup system patent was in France and maybe it was cheaper to stamp the longarm with Paris as it was going to be imported to the U.S. of A. There was some reason for a Belgian maker to send his price point arms, or components, to France and then on to the U.S. of A. All of the ones I've seen had "Patent" stamped on them instead of Brevete.

Kind Regards,

Raimey
rse