It's no Krylon or Rustoleum paint job, it is hard automotive quality paint. The liner appears to be original German? It was obviously taken out to paint it and put back in.
I got this many years ago and it's been collecting dust ever since. My original goal was to sandblast it and paint it a proper color but I never got around to it. I only collect USGI stuff and mostly firearms and bayonets, not field gear. I can't tell you much more about it other than what the pics show. The item "WW2 German helmet, gloss black biker helmet" is in sale since Wednesday, October 05, 2016.
This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\Germany\Hats & Helmets". The seller is "garandnut" and is located in Manchester, New Hampshire. This item can be shipped to United States.