Bill d isere and knewit: That's how I imagine the collegial tone among us.
Bill is right, it's a Büssing NAG 900 with cab and body by Auwärter. But from which Auwärter? Blocked for Bill to give the answer.
I have no clear information about the year of manufacture. My source says mid-30s, another says 1936, so let's leave it at mid-30s.