It is a DKW F91 sports coupe, built by Belgian coachbuilder D'Ieteren in 1954 for Edouard Boucquey. The body was made of aluminium.
In 1955 Boucquey took part in various rallies with it, including Liège-Rome-Liège (3rd place, see puzzle photo), Circuit Nivelles (3rd place overall, class winner 1000 cc).
There are said to have been contacts with the developers of the DKW Monza.
I figured out, that Edouard Boucquey owned the very first DKW Monza, that was produced after the 1955 IAA. (The showcar of the IAA wasn´t most likely roadworthy. It was upgraded later to become DKW Monza #2. According to my informations, the car is still existing in France.).
Boucquey used his Monza for several races in 1956.
So somehow there is a link from the dÍeteren DKW to the DKW Monza.
See also <<link deleted>>