Why Were the French Unable to Defeat the Vietnam in the First Indochina War?

The French lost the First Indochina for a variety of reasons, such as the inability to match the Vietnamese War machine, lack of vision regarding the end of colonialism and independence for Vietnam, and finally the disaster which was Dien Bien Phu and the reaction at home.
The French had controlled the country from the 1850's up until 1940 when during WWII Japan moved into Indochina, taking control of the country, but leaving it under the rule of the French. In 1945 Japan looked as if it was defeated and so announced Independence for Vietnam. The French were now intending to reclaim territory which they considered rightfully theirs as colonial land, using their conventional, modern day military system which had won the Allies World War I.
The Vietnamese, for the best part of the conflict represented by the Viet Minh were tired of Colonial oppression, and following Japans announcement on an Independent State of Vietnam, The Viet Minh, under the leadership of Ho Chi Minh were quick to announce themselves as the rulers of the newly formed "Democratic Republic of Vietnam". …