French Cavalry

Cuirassiers were regarded as the decisive arm of the army by Napoleon Bonaparte.
While the other forms of horsemen in the Grande Armee had their roles to play, it was the heavily armoured Gros Freres (Big Brothers) that could turn a battle with their sheer weight.
To carry the cuirass (breastplate) and iron and brass helmet, the trooper needed to be big and strong.
In accordance, the horse to carry them was large and together the cuirassier and his mount would hit opposing cavalry with brute force.

Dragoons

France's dragoons were the mainstay of the mounted arm of the forces and were capable of either scouting, or being involved in battle-winning charges.
As well as straight heavy-cavalry sabres, dragoons had pistols and short carbines and these allowed them to dismount and fight on foot as highly mobile infantry.
This advantage saw them used widely in the anti-guerrilla warfare in the Peninsular War, as well as on independent roles on the army's flanks.

Some of the most feared cavalry in Bonaparte's armies were the Polish lancers, who gave no quarter.
The British discovered this at Albuera when Polish lancers, covered by a rainstorm, managed to get the jump on a redcoat brigade and wiped it out within seconds.
Lancers were excellent against infantry in square - where their lances could outreach the infantry bayonets - and also in hunting down a routed enemy.