Following France's armistice with Germany in late June 1940, Boisson at first vehemently demanded that French forces continue fighting, but he was soon won over to the Vichy government when its head of state, Marshal Philippe Pétain, sent him to Dakar as governor-general of French West Africa and high commissioner for French Africa. Ambition persuaded the energetic Boisson to accept the new regime. Arriving in Dakar on 23 July 1940, he banned Germans from the city, but in September 1940, he also defeated an attempt by Free French leader General Charles de Gaulle to take over both Dakar and the French battleship Richelieu, which was sheltering there.
After the 8 November 1942 Allied landings in North Africa, Admiral Jean Darlan reached an accord with Lieutenant General Mark Clark, deputy U.S. commander, and ordered Boisson to bring French West Africa into the Allied camp, instructions Boisson took 10 days to obey. Nonetheless, U.S. President Franklin D. Roosevelt rather admired the straightforward Boisson's uncompromising and evenhanded style, which, though brutal when necessary, was direct, honest, and effective. Boisson's relations with the Allies were cold but correct, and Roosevelt initially insisted that de Gaulle leave him in his post; only on 1 July 1943, after de Gaulle became head of the Provisional French National Committee, was Boisson dismissed.
Ignoring Roosevelt's protests, de Gaulle ordered Boisson arrested on 15 December 1943. He was then incarcerated for two years without trial and only released on grounds of ill health. In 1948, Boisson was summoned to a trial before the French High Court of Justice, but before proceedings began, he died suddenly, on 20 July, at Châtou, Paris. Priscilla Roberts
Hitchcock, William I. "Pierre Boisson, French West Africa, and the Postwar Epuration: A Case from the Aix Files." French Historical Studies 24, no. 2 (Spring 2001): 305–341.; Hoisington, W. A., Jr. The Casablanca Connection: French Colonial Policy, 1936–1943. Chapel Hill: University of North Carolina Press, 1984.; Ordioni, Pierre. Tout commence à Alger, 1940–1945. Paris: Éditions Albatros, 1985.; Paxton, Robert O. Parades and Politics at Vichy: The French Officer Corps under Marshal Pétain. Princeton, NJ: Princeton University Press, 1966.