When I first saw the name "Nicolas", I automatically thought "Bis", but I don't think that's the gunsmith here. The blurred out last name on the lockplate sure don't look like that.
The stocking, barrel, and hardware, however, do look very Spanish. The lock, not so much. The lock looks very French, and I get a French impression from the engraving "NI_OLAS L__NC__H A. _______".
Looks like a French or Belgian pistol done in Spanish style, which was all the rage.