More seriously I have 6 (probably more) pre WWII German cameras and the build quality is excellent, you may need to just tweak the lock with a screwdriver so it works, it's a pre WWII camera so give it a chance.
You need to work out how the catch works then use an Irish screw driver (Hammer) and tap the relevant part gently back into place.
It shouldn't be too difficult, I had to repair a German 9x12 camera I bought that had been opened with a bottle opener and very badly damaged, but when you realise how they are meant to work it's a lot easier.