Belgian or French Folding Sword
The ivory handle with a steel thumb release, the blade swinging to an open blade leaving a guard, signed blade, 53 cm high when open.
Made by Gilson. I can’t make out the city name.
Belgian Folding Sword Demonstration
This folding, pick lock automatic cutlass came into the shop for a new spring. Blade is 9-½ in. long , overall it is 20 in. open. Made in the late 1800s by Arnold Namur in Belgium.
how easy would it be to knock it closed and guillotine their fingers off?
The piece that locks the blade in the closed position also prevents the blade from closing through the knuckle guard. I’d say it would take some effort to guillotine one’s fingers.