I discovered aircraft models with German swastika are forbidden on eBay. Models lacking swastika or with it painted over I guess are ok.
I listed a few built-up models and had auction for ME-262 cancelled for above reason. Also forbidden is listing model with swastika Photoshopped out.
This is evidently a somewhat new policy as I had listed 200+ built-ups a couple of years ago and nary a BF-109, FW-190, etc auction were cancelled.