The hole in the slide stop is the tip off. They were good guns, reliable and rugged, but heavy as hell. With a full magazine they are a bear to even pick up, let alone carry. Of course that means they shoot well; recoil is close to non-existent. They were the French service pistol for a while, IIRC.
They are hammer fired and use a rotating barrel in a basic Petter design. The 15 round magazine gives them the nomenclature, P-15.
The original finish is a very smooth, gray, phosphate coating over an excellent polish. That one has lost some of its finish on the edges, but appears to be in good condition. It would be no surprise to find French weapons in Equatorial Africa; they had colonies in that region for years and still have a substantial military presence in many of those countries.
Jim