Battle of Dien Bien Phu

About 5 p.m. in the command bunker

The Viet Minh's final offensive had begun on 6 May. During the afternoon of 7 May 1954 its forces captured the remaining central French strongpoints and reached the command area.

In the late afternoon, Christian de Castries reported to headquarters in Hanoi — René Cogny held the last radio contact — and ordered the central garrison to stop fighting.

Viet Minh troops entered de Castries's command bunker and captured him there, at about 17:00 local time.

Isabelle fought on

The end was not a single valley-wide moment. The isolated southern strongpoint Isabelle did not cease resistance with the central camp; its attempted breakout failed and it was overrun early on 8 May.

French accounts describe an order to cease fire and subsequent capture rather than a formal capitulation ceremony. About 10,300 French Union personnel were taken prisoner, roughly 4,400 of them wounded, at the close of a battle conventionally dated at 57 days.

What 7 May did not settle

The defeat did not itself end the First Indochina War. Fighting elsewhere continued until the Geneva ceasefires.

The Geneva Conference had already convened before the camp fell, and its Indochina phase opened on 8 May; the defeat transformed those negotiations rather than causing the conference to be called. The 17th parallel they later fixed was a provisional military demarcation line for regrouping forces, explicitly not a political or territorial boundary.