This miniature muff pistol bears the Liege proof-mark, initials SP, and letter L on the barrel. There are no other marks that I see. Only 14 cm-long from the butt to the muzzle, it was small enough to fit inside a lady's winter muff, purse, or inside a stocking. Nevertheless, with a caliber of about 11 mm it packed quite a wallop for a surprised intruder. The action is quite sound, and the hammer cocks good. 
Above average in quality, then most "run of the mill" percussion single-shooters that came out of Belgium at the time, it comes with its period velvet pouch, no doubt the handy-craft of the lady that carried it for personal protection. Antique, no FFL needed.