Is it a ca.1926 Dürkopp Sportwagen?
EDIT:
I´ve found it as the Dürkopp Sportwagen Typ P 8 B; 2 liter, 60 HP, built from 1925-26
And the photo might show the great Hans Stuck standing next to the car at the Solitude race track, who later drove the mighty Auto Union race cars of the 1930s.