Why the French lost French and Indian War?

Answer 1

They lost against the Viet Minh.

They lost due to the fact that they were greatly outnumbered, 15 000 french to 50 000 Viet Minh. (approx. most sources have similar numbers)

Also the tactics the french had used was not suited to the environment. They used maps for they did not know the area which were often found by members of the VM and were used against them to find their where-abouts.

The FEC (french) had under estimated the Viet Minh and thought that they would be unable to get supplies and warfare equipment up through the harsh terrain and surrounding trees and mountains in the jungle land. Though that's exactly what they had done.

But most importantly is the VM tunnels, in 57 days the battle of Dien Bien Phu had ended with the FEC defeat. The FEC had made many forts which were taken down one by one by the VM through their use of digging secret tunnels through to each fort. This had occured march-may 1954.

Answer 2

After the British managed to make them surrender in Montréal they were unable to support their battles elsewhere and ceded Quebec (French Canada) to Britain.

Answer 3

The French lost mostly because the British had a stronger navy and more weapons. Don't forget in this war there was the French, the Indians, and the British.