In 1949 Mairesse joined Vallée's team, Ecurie France, to race the Lago-Talbot and took fourth place at Pau and fifth at Albi. In 1950 he finished second at Le Mans with Pierre Meyrat using a single seat Talbot. Towards the end of that season the Vallée team closed and Mairesse purchased the Le Mans car and a Lago-Talbot T26C, which he used to enter the 1950 Italian Grand Prix, from which he retired, and the Swiss and French Grands Prix in 1951, finishing 11 laps down and "not classified" on both occasions. Thereafter his business commitments curtailed his involvement in racing and he sold his cars in 1952 appearing infrequently in other owners' machinery.