Napoleon understood that his heavy cavalry lacked the maneuverability of Frederick the Great's cavalry, so he tried to redress this disadvantage by increasing the number of riders attacking.
Therefore, the cavalry started to attack at a trot, as it was only at this pace that it could hold order. However, this kind of attack caused great casualties, both among the cavaliers and horses.
In order to reduce casualties, the heavy cavalry had been equipped with cuirasses. They became the elite cavalry force of the entire Grand Army. This type of cavalry was mostly used for powerful frontal attacks and for disrupting the enemy's ranks, the success of which usually predetermined the outcome of the entire campaign.
Cuirassiers were armed with broadswords and a brace of pistols. Subsequently, the most effective firing range for them was close up, when riders had already penetrated the enemy lines.
Cuirassiers were the best at assaulting enemy cannon, due to their cuirasses, which provided superior protection not only from bullets and arrows, but from case-shot as well. They could withstand a volley which would surely decimate another mounted unit.