When the Gestapo made inquiries about him in March 1943 he went underground and joined the French Forces of the Interior.

He was political director of the daily Nouvelle gazette of Biarritz, and wrote regularly for Sud-Ouest, Le Nouveau Journal and L'Eclair des Pyrénées.

[1] Petit was secretary of state to the President of the council from 14 March 1952 to 8 January 1953 in the cabinet of Antoine Pinay.

[2] He worked to develop the tourist industry in France, in his department, and in the upscale resort of Biarritz, where he was mayor until 1977.

He favored measures to make it easier to open hotels, to consolidate natural sites and to restrict outdoor advertising near listed buildings.

Under his leadership the municipality renovated the Hôtel du Palais, one of the finest luxury hotels in France.