The French General asked why the British soldiers wore red uniforms. He was explained, it was red because that way if a soldier was bleeding, other soldiers would not notice and panic. The French General promptly order khaki colors for French soldiers.
Ironically, it was the French government’s insistence on red pants for their troops (along with a nice shiny brass belt buckle front-and-center) that helped them lose over 500,000 troops in six months in 1914.