You might be able to get considerable info the man who owned this helmet by contacting Jean-Loup@Gassend.com, who posts all sorts of interesting analyses of WW II war dead based on things like found dogtags, marked helmets and other equipment, etc. He posts on Youtube as CrocodileTear.
Sometimes a history to go along with an item increases its value and sometimes it doesn't, but I think you'll find the journey interesting.