How did France become embroiled in Vietnam, in the first of long wars of decolonization? And why did the French colonial administration, in late 1946, having negotiated with Ho Chi Minh for a year, adopt a warlike stance towards Ho's régime which ran counter to the liberal colonial doctrine of liberated France? Based on French archival sources, almost all of them previously unavailable to the English-speaking reader, the author assesses the policy that emerged from the 1944 Brazzaville conference; and the doomed attempt to apply that policy in Indo-China.