For 1929, Rothschild decided to upgrade to a full Grand Prix-specification Type 35C. In fact, he was so enamoured with the vehicles, he ordered three. Using one of the new cars, "Georges Philippe" was entered into the Grand Prix d'Antibes. In a field that included René Dreyfus and Philippe Étancelin, both race winners many times over, Rothschild led the race until he crashed out on the 36th lap. A mere two weeks later, with the car rebuilt, Georges Philippe finished a highly creditable fourth at the inaugural Grand Prix Automobile de Monaco, behind winner William Grover-Williams.