I am not seeing anything that indicates Belgian origin. Not say there is no Belgian connection, as there was much interaction between Belgium and France. It does resemble the Brun action. Brun was active 1849-1872. Here is Brun pistol:
http://littlegun.be/arme%20francaise/artisans%20a%20b/a%20brun%20gb.htm

There should be some proof marks under the barrels.

This Brun pinfire is owned by The Metropolitan Museum of Art.


This is a 14mm pinfire Husqvarna with Lefaucheaux release:


Pete

http://www.damascus-barrels.com/Movie.html