It's an Adrian, but that's all that I know about it. Any other idea?
Thank you all!
Hi Adi, it is a Peruvian M34 Steel Helmet.
Designated the Model 1934 by the Peruvian Army, this helmet is actually the French Model 1926 with the sun and crown insignia of Peru. This helmet was used until the 1960's when it was replaced by the American M1 steel helmet.
I wonder what is this helmet doing in Siebenburgen.
Thank you for your complete answer.