I bet this German took the rifle from a French/Belgian farmer, or it was confiscated and later liberated by him. I doubt it was one of his personal civilian weapons or a issued weapon. If its his own civilian gun, it would have German proof marks somewhere.
It also looks like Browning have done a wonderfull job on the restoration, I didn't know they restored vintage guns, are they reasonably priced? I don't mind paying when it reflects the quality of work!