You're right, CMSMJ1, it was Hans Heyer who, despite showing some pace, only managed in qualifying to be the third reserve driver. Nevertheless, after the start of the race, he drove down the pit lane and raced after the pack.
Transmission problems meant he only got to drive for 9 laps, where he managed to be 22th fastest driver. The marshalls made no move to black-flag him and this event will be forever discussed if it should be a DNQ or a DSQ.
Also, the motivations behind this unique situation have never been clarified, although potential clues may be the need of some exposure to Mampe Halb und Halb, ATS' sponsor for this event and the fact that Heyer was an experienced and reputed driver, potentially with some influence on the race stewards.
Heyer even has at
his site a video of a lap of the Hockenheimring filmed from the ATS, that year.