The new commander of French forces in Vietnam, General Henri Navarre, decided soon after his arrival in Vietnam to end a Viet Minh offensive underway in neighboring Laos. To accomplish that, Navarre believed his forces would have to capture and hold the town of Dien Bien Phu, sixteen kilometers from the Laotian border. But Navarre could not have picked a worse target. Control of Dien Bien Phu was critical for the Viet Minh since the town was an important link in the China supply route.
In November of 1953, French forces occupied Dien Bien Phu with paratroop battalions. Units from the French military post at nearby Lai Chau were sent in as reinforcements.
During that same month, Ho indicated that his government was willing to examine French proposals for settlement. By February of 1954, a peace conference in Geneva was set for April. To make sure that negotiations went their way, Viet Minh strategists thought they should attack a French fortified camp - like Dien Bien Phu. If they were successful, Ho and his government in Hanoi would have a tremendous advantage at the peace conference.
A siege of Dien Bien Phu began on March 13, 1954. The Viet Minh had concentrated nearly 50,000 regular troops, 55,000 support troops, and almost 100,000 transport workers in the area. Chinese aid (mostly ammunition, petroleum, and some large artillery pieces transported hundreds of miles from the Chinese border), reached 1,500 tons per month by early 1954.
The French garrison of 15,000 soldiers depended on air transports for their supplies. But that was cut off by March 27, when Viet Minh artillery made the airfield unusable. An elaborate system of tunnels dug in the mountainsides enabled the Viet Minh to protect their artillery by moving it around - without discovery. Using a hundred miles of trenches, the attackers closed in on the French encampment. In the final battle, the Viet Minh used human wave assaults to take the perimeters. The big prize in the perimeter battle were French guns which the guerillas turned on the main camp.
With no options left, the French garrison surrendered on May 7. The siege had cost 25,000 Vietnamese and 1,500 French troops their lives.
The next day, Indochina peace talks began in Geneva. The next decade, despite French warnings, the United States began to repeat France's mistakes.