Hi everyone! This is my first post on any forum, so I hope this works...
The closest thing I can find to this thing, judging by the weird toe of the grip and the two screws kinda overlapping just below the safety, is an "F.A."
It was made by Francisco Arizmendi of Eibar, who also made the charmingly named "F.A.G."
No way to be sure, since I can't find an exact match though... Guns of a similar config. were made by Auguste Francotte and J.B. Ronge Fils, both of Liege.
Hope this helps!