Well done!
The X on the radiator grille is the key to identification.
Winning car - at an average speed of 98.59 kph!
Thought I had you foxed for a while....
GF
What: Chenard & Walcker Sport 3-Litre
Who: André Lagache & René Léonard
When: May 26-27 1923
First winners of les 24 Heures du Mans
Stupid answer!
It's:
What: Salmson VAL
Who: Robert Benoist
When: 16 September 1922 - Le Mans (IV Grand Prix de l'U.M.F. Cyclecars)
Benoist became an agent for SOE in WWII along with fellow GP drivers Jean-Pierre Wimille and William-Grover Williams. He was captured in Paris in June 1944 and shot by the Nazis at Buchenwald on 11 September 1944.