We have a winner from the comments:
Chris Saddler Sam commented:
DKW Hummel Victoria (google it!)
Hell of a catch!
Warren Wood sends in this mystery bike… Interesting but not a clue on my part.
Mystery bike in Paranesti,Thrace, Greece. —also— my ancient [1989?] Honda AX1 250cc while on tour of the Rodolpi Mts, same area.
A hugely underappreciated little Honda
Motorcycle Photo Of The Day 
dkw hummel victoria (google it!)
I was gonna say that it looked East German, like an MZ, but Chris is probably right. Gotta be pre-1960 cold-war issue…150 cc?
http://www.motorcyclespecs.co.za/model/Classic/DKW%20Hummel.htm
CHEERS MY MOTORHEAD PALS
🙂