That's the insignia of the NVA, the armed forces of the GDR. There's a certain similarity to the the winter variety of a People's Navy hat, worn by the ranks "Unterleutnant/ Leutnant/ Oberleutnant zur See" and "Kapitänleutnant" (=sub-lieutenants and lieutenants). Check for yourself: http://uniformen-der-ddr.blogspot.de/2012/09/volksmarine-dienstuniform-offiziere_30.html ...though yours is missing the colors of he insignia. I'm clearly not an expert on the topic, so I can't tell you if it's real.