From the handle (which is a pretty good match for my Hoffritz travel slant--manufactured by Merkur), I'd guess it was a Merkur of some kind, but not sure beyond that. There were lots of German razor manufacturers in the last century, though, so it could be one of the smaller companies.
Hmmm... I can't say whether this is German or not but it resembles more of a military issued razor in my opinion. Gillette and a few other companies made military issued DE razors around the time of the war and this looks very alike to those made during the same time. Now, whether it is German or not is still a mystery to me - hopefully someone chimes in with an answer.
I've seen a few now, I wouldn't be surprised if it wasn't made by someone else and re-branded to others. ie made by Davo and rebranded Merkur or whatever. Shouldn't it be hergestellt in Deutschland?