Heer four-pocket service tunic, a so-called ornamented field tunic (Geschmückte Feldbluse), without piping to the front and cuffs. It is designed with four pockets and French cuffs, like a normal officer's field tunic. 

Branch: Infantry.
Shoulder boards: white base. Hauptmann rank. Sewn-in type. Silver pips. 
Collar tabs: mounted on a dark green base, and has a white stripe. Officer's type. Period time attached by machine.
Collar: Dark green. No mothing.
Breast eagle: Hand-embroidered officer's type. Attached by hand.
Buttons: Complete and period time attached. Field-gray.
Lining: Silk. Period time attached tailor's tag, "Decker, Bayreuth"

The tunic comes with a 6-award ribbon bar and also silver adjutants' aiguillettes attached to the right shoulder. Both don't seem to be original to the tunic.