The slide release makes me think it's a Koningsberg made 1911 (or 1913, as the Norwegians call it), calling it a Nazi handgun I'd assume that this one was made under the occupation.
It's obvious, but I never really considered the idea of that for whatever reason. Looks like new too.>>33373898
If you were going to have the Nazi German flag as a pair of grips, in color, the obvious choice would be a plain red grip, with the white-backed swastika in the middle, where you'd otherwise find the grip medallion on say, a Colt (except much bigger, to stand out). Also it should be clean and clear colors, none of that sparkly shit it has going there.
That said, for the colors chosen, I would have gone for an Iron Cross. And probably a nickel plating on the frame and slide.