Jack, don't worry about him firing it, as it's a Warnant system "flobert" type that's missing the hinged breechblock:
http://www.littlegun.be/arme%20belge...ulien%20gb.htm
This was a weak point, and the arms of the block often cracked at the screw holes, especially if someone tried regular .22 ammo.
A 1915 gunsmith's parts catalog listed unfinished warnant breechblocks @ $8 a dozen!: