The French inadvertently played a major role in precipitating the Pacific War, but only a minor role in the war itself. France in 1940 had a colonial empire in the Pacific that took in French Indochina— roughly corresponding to the modern nations of Cambodia, Laos, and Vietnam — and the island groups of New Caledonia and French Polynesia. When metropolitan France capitulated to Germany in June 1940, Japan saw an opportunity to extend its power in southeastern Asia. The subsequent chain of events led to war between Japan and the United States, Britain, and the Netherlands.

National Archives.
Via Wikipedia
Commons
The French capitulation put Paris under German
control, and the French government reestablished itself at Vichy in an
unoccupied zone of France. Unsurprisingly, this government was
dominated by extreme right-wing politicians who were sympathetic to
Nazism. A counter movement, the Free French, grew up under Brigadier General Charles de
Gaulle, the Under Secretary of State for National Defense and War, who
opposed the French surrender and fled to London when France fell. de
Gaulle
was determined to restore French honor by fighting alongside the
Anglo-Americans while standing up for French interests. de Gaulle's
Free
French movement spanned the political spectrum; its flag, the Tricolor
with a superimposed Cross of Lorraine, represented the union in common
cause of the forces of Christianity on the right and the French
Revolution on the left.
In September 1940, the Japanese pressured the Vichy government into allowing them to station troops and use ports and airfields in northern French Indochina. When the Japanese expanded into southern French Indochina in July 1941, the United States, Britain, and the Netherlands responded with an embargo on oil that threatened to strangle the Japanese military in China. Japan responded with the attack on Pearl Harbor, the objective of which was to cripple the U.S. Pacific Fleet long enough to permit Japan to conquer the oil fields of the Netherlands East Indies and Borneo.
With the coming of the Pacific War, the French colonies in the Pacific more or less fell in line with the side that was more powerful in their neighborhood. French Indochina, located deep in the Japanese sphere of influence, remained loyal to the Vichy government. The French governors of New Caledonia and French Polynesia were at least nominally loyal to the Free French movement. Neither side contributed much in the way of military forces to the war, though the bases at Noumea and Espiritu Santo were important to the Allies during the South Pacific battles, and the Richelieu was a welcome reinforcement to the British Far East Fleet.
References
The Pacific War Online Encyclopedia © 2006, 2010 by Kent G. Budge. Index