Born Feb. 7, 1920, in Hauteville, Fribourg Canton. Figure in the Swiss working-class movement.
Magnin is the son of a worker. From 1947 to 1954 he was chairman of the trade union of workers of the machine-building and watch industries of Geneva Canton. He joined the Communist Party of Switzerland in 1943. He became a member of the Central Committee of the Swiss Labor Party in 1949, and in 1954 he was elected to the Steering Committee (renamed the Politburo in 1971) of the SLP. Magnin served as the editor of the SLP newspaper Voix ouvrière from 1954 to 1970 and as the political director from 1972 to 1975. From 1970 to 1978 he held the post of political secretary of the secretariat of the Geneva section of the SLP.
Magnin was elected a member of the Secretariat of the SLP in 1974 and became the party’s general secretary in May 1978. He was a member of the World Peace Council from 1954 to 1960. Magnin has been a member of the Grand Council of Geneva Canton since 1945.