[QUOTE=fernando]A big pistol indeed  
 
 
If you don't mind, i would suspect the writings of France and Marseille on the barrel and on the lock. It could be a trading illusion.
The Liege proof mark is there to remind you. 
Regards
Cerjak
Good eyes Fernando !
Yes many barrels from French guns & pistols  was made in Belgium but the lock is from Marseilles  it's not  the first time  I see that.
See the following pictures from a french gun  with mark from ST OMER ( north of France and Liege  proof mark too.
Regards
Cerjak