For our non-German speaking members:
"The short wheelbase had also surprised me. For me, the basic shape of the fenders, in combination with the frame of the windshield and the GDR license plate, was the main reason for thinking of a "chopped" early IFA F9 convertible sedan (the B-pillar also looks cut off). Of course I may be completely wrong and it is best to look again for the right photo for comparison."