Provisional Government of the French Republic
Following France's liberation, Lefaucheux was elected to the Constituent Assembly of the Provisional Government of the French Republic, representing the Organisation Civile et Militaire. She returned to the Constituent Assembly as a deputy in 1945 and was also elected to the Municipal Council of Paris, where she was vice president. In 1946, after the adoption of a new constitution, Lefaucheux was elected to the first Council of the French Fourth Republic.