In the 1950s, the brothers Jean and Pierre Hémard owned the French racing car manufacturer Monopole , which produced racing vehicles with a small engine displacement and Panhard technology. Jean Hémard was also active as a racing driver and competed a few times in the Le Mans 24-hour race . Three times, in 1950 , 1951 and 1952 , he achieved class victories with the self-made racing cars.