Roger Lebranchu spent two years, from 1943 through 1945, in the Buchenwald and Auschwitz Concentration Camps during World War II. While there, he was forced to work to the point of exhaustion, but managed to flee when the camp was evacuated near the end of the conflict. Physically weak upon his return, he eventually began rowing with the Société Nautique de la Basse Seine in Courbevoie and was selected to represent France in the coxed eights event at the 1948 London Olympics. There, alongside Pierre Clergerie, René Boucher, Jean Bocahut, Erik Aschehoug, Alphonse Bouton, Pierre Sauvestre, Pierre Fauveau, and Robert Léon he finished last in his opening heat and did not take part in the repêchage. This was Lebranchu’s only major international competition.