 Paul Flamant matriculated in 1913 at the École Normale Supérieure (ENS) as the highest-rated student, but before graduation went to the front in WW I as a second lieutenant in the French army.He was wounded at Charleroi and taken prisoner.He spent almost four years as a prisoner-of-war, then returned to the ENS and passed his agrégation (and was the highest-rated student for that year of examinations).