The son of a trader in
Brest, Chupin trained as an engineer and became a pilot in the
French Air Force. He owned a plumbing and heating business prior to entering politics, inspired by
Charles de Gaulle. Chupin was elected
Mayor of Brest in 1947, following the great success by other
Rally of the French People (RPF) politicians. He was re-elected in 1950, although his second term was marred by the death of , an opponent who was killed during a demonstration harshly repressed by the police on 17 April 1950. In 1951, he was elected to the
National Assembly for
Finistère, still a member of the RPF. During his mandate, he moved to the centre-left and joined the
Democratic and Socialist Union of the Resistance (USDF) following the dissolution of the RPF in 1953. That year, he failed to be re-elected as Mayor of Brest, losing to
Popular Republican Movement candidate . Chupin supported
Pierre Mendès France and his policies, moving further away from his previous
Gaullist ideals with his support of the
Treaty establishing the European Defence Community. In
1956, Chupin lost his seat in the National Assembly, earning only 3.2% of the vote. ==References==