Thanks for your fast reply. Very helpful information. I'm glad that at least the shell is authentic I have attached some more pictures of the liner. I removed the white chord and pulled up the leather. It feels like leather, although very thin. The liner band is black, feels like some kind of hard plastic and it extends up into the top of the dome. With felt attached on the ring that goes around your head, probably as some kind of sweatband. On the front there some kind or orange foam, feels like shammy. If you google on German Helmet WWII liner you get several results that match my helmet's. So indeed a German look-a-like, though a cheap one.
The inside of the helmet is painted in dark green. But there also appears to be a layer of transparant glue, probably used to - try to - fasten the liner I guess.
Seems like a lot of energy has been spent on this helmet, unfortunately in the wrong direction Well, you can't always be lucky..... and indeed, at least it's green.
Best regards, Danny