Ernst Udet's specially modified personal Udet U 12a aerobatics biplane, D-822. Aircraft was painted all red, with white trim. The two detail enlargements of the photo show the covered front seat as well as the Siemens Motor, Mobiloel, and Bayer. Flugzeugwerke AG Augsburg logos.
As can be seen in the lowermost detail enlargement, the person standing on the left in the main photo all but obscures the white flamingo painted on the fuselage between Udet's name and the aircraft's registration.
Photo very likely taken in the late 1920s, but exact date and location are currently unknown to me. (Fischer collection)