This is a carte de visite or CDV photograph of a man in a military uniform from Posen which was at that time part of Prussia.  The photographers' logo is on the back and they were A. & F. Zeuschner of Posen.  There is handwriting on the back with what is probably an identification of the man and some numbers.  They are written in a language that I can't decipher.  The photograph itself is not affected by the uneven margins.