His activities against the Indochina war, caused him to spend a few weeks in prison in 1949, then sixteen months in hiding in 1952–53. He then resumed his studies, became a professor in 1954, passed the CAPES (diploma in teaching - secondary schools) in history in 1958, his diploma in teaching higher education in 1960 and was appointed lecturer. At the same time, he was responsible for the founding of the Union of Communist Students.