I think everybody is stumped on this one: You are looking for something unique.
Well, ok. I think that we established earlier that it was the site of the 1900 Summer Olympics. The most unique feature was that they were the only Olympic Games not run by the IOC. Control was handed over to a special committee associated with the 1900 Exposition Universelle.
At the center of the picture is the Velodrome de Vincennes. It was the main stadium for the Games, although Athletics (or, as we Yanks say, Track and Field) was contested elsewhere. The velodrome was also the finish of the Tour de France from 1968 - 1974, a period that included the five victories of Eddy Merckx.
No valid answer as yet. Are you all still stumped?
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII