uniforms
did the french soldiers have to wear wool uniforms and thick wool socks
in this type of environment ???
In real life they would have worn the light weight cotton khaki colored uniform that you see some of the Legionnaires wearing (this uniform was the primary uniform in the Jean Claude Van Damme movie "Legionnaire" which is set in the same time period as this movie - the 1920s). This uniform was introduced in 1915 for the French units being sent to fight the Turkish in the Middle East.
The famous "Beau Geste" style uniform with the heavy wool blue jacket (ie: the classic French Foreign Legion uniform) was declared obsolete in the early 1900s. Though the Kepi Blanc survives in the French Foreign Legion right up to the present day.