French Cuirassiers, still wore shining helmets with horse hair tails similar to those of Napoleon's cavalry. Later in the war they changed to more serviceable tin hats.

During the early days of October 1914 the BEF were moved from Aisne to the neighbourhood of Ypres in Belgium.

Capt. Brownlow DSO later wrote this account describing his first meeting with French cavalry.

"When we arrived at Zelobes there were billeted in and about some  regiments of French Cavalry. "On October the 14th I witnessed one of the most dramatic incidents I have ever seen.

I saw a spectacle which made me rub my eyes. There standing at a cross roads was a group of officers in magnificent uniform of the French Curassiers - curved metal helmets with flowing horsehair tails, burnished cuirasses, gold sword belts, red breeches and black polished thigh boots.

The group consisted of generals and staff officers.

As I passed an officer called me & asked if I knew any information about the British line. I had just finished explaining our dispositions, when suddenly someone cries out "V'la" and all eyes turned on the road, where we saw an officer on a horse.

As he got closer I saw that his uniform was covered in mud and his cuirass tinged with rust. 

His horse was exhausted and flecked with foam and blood. He drew up, saluted, dismounted very slowly and holding out an envelope, said "Mon General".

As he did so his face, which had been white and set, turned ashen, he staggered and fell to the ground before that splendid group of men. In the back of his cuirass was a jagged hole, from which thick blood was slowly oozing".
Source "I was there" magazine (1930)