Sunday 21st June 1931
The XVII Grand Prix of the AC de France was run to the 10-Hour International Formula, demanding two drivers per car. Three strong official factory teams from Alfa Romeo, Bugatti and Maserati provided the main battle. The early leader was Fagioli in the 2800 Maserati until Chiron in the twin-cam Bugatti passed him. After one hour, Luigi Fagioli was again in first place next came Louis Chiron, Rene Dreyfus, Albert Divo, William Grover-Williams, Marcel Lehoux and Giuseppe Campari, the fastest of the 2300 Alfa Romeo drivers, in seventh place. For the first time since WW I, there was a German entry in the French Grand Prix, the independent team of Rudolf Caracciola/Otto Merz in a huge Mercedes-Benz. They held eighth place after the first lap; then fell back to 13th before retiring later. The Rene Dreyfus/ Pieto Ghersi pair twice held second place, but maintained third position during most of the first half of the race.Out of 23 starters only 12 finished the long race. The independent drivers were the first to retire. Jack Dunfee (Sunbeam) broke down at the start. Ivanowski (Mercedes-Benz) and Lehoux (Bugatti) disappeared before the the second hour ended. Scott’s 1920’s Delage broke down during the third hour to be followed by the Caracciola/Merz Mercedes-Benz in the fourth hour. The first factory car to retire was Fagioli/E.Maserati with the 2800 Maserati during the fifth hour. Five Bugattis retired over the next laps, all caused by mechanical failures. Chiron/Varzi (Bugatti) dominated the race and won three laps ahead of Campari/Borzacchini (Alfa Romeo) and five laps in front of Clemente Biondetti/Parenti (Maserati). Henry Birkin/ George Eyston (Maserati) an independent entry finished fourth. A total of 12 cars were classified but only 10 were still driving at the end while Divo/Bouriat and Tazio Nuvolari/Giovanni Minozzi made it on distance alone as their cars broke down near the end.