Born in Suarce, Bergeron was brought up in the Plymouth Brethren faith, but broke with it while still at school, joining the Socialist Youth.
[1][2] After the war, Bergeron moved to Belfort and to printing, and in 1946, he was elected as secretary of the local typographers' union.
[1][2] In 1950, Bergeron began working in FO's national office, where he was a notable voice in support of Algerian independence.
While initially highly controversial, he was eventually able to get a union position agreed, and his skills in this led him to win election as general secretary of FO in 1963.
He largely maintained existing federation positions, pushing for moderate reforms, and working closely with government from both left and right, but strongly opposing the French Communist Party.