Like Jim said, Dean nailed it. Here's the link: http://www.lehussard.fr/frameGeneral...Cat=SYS_ANCIEN
PISTOLET DE GENDARMERIE Mle AN IX. The guns were issued to law enforcement.
My pictures don't show the rounded lockplate. But they are rounded on the hammer side..
All the markings (according to the link) are correct. 1811 on the stock and barrel. The Lockplate engraving is the same. Looks like one of the pair had a lockplate replaced or re-engraved.
Still trying find out what the "B" with the crown on top means that is stamped on the lockplate.