The newspaper article in the Spandauer Volksblatt of 19 February 1972 shows that he attended an art school between 1912 and 1916. Now there is the first indication that he was enrolled for one semester at the Akademische Hochschule für die Bildenden Künste in the winter semester of 1912/13:
Entry on Fritz Neumann in the index of names for the winter semester 1912/13
The excerpt comes from the Alphabetical index of names WS 1909/10 to SS 1924 of the Academy of Fine Arts, page 92, shelfmark UdK Archive 6-204
Thanks to Dr Anastasia Dittmann from the Archive of the Berlin University of the Arts for pointing this out.
