[1] Guyot took part to the Wars of the Third and Fourth Coalition with the Grande Armée, holding the rank of squadron commander in the Guard chasseurs-à-cheval regiment and being noted for bravery at the Austerlitz and Eylau.

After the battle of Vauchamps, Guyot left the Guard horse artillery company that was attached to his division in an exposed position, with orders to join him in a precise location at nightfall.

Guyot did not leave behind a cavalry escort and a guide, which resulted in the artillery company being ambushed that night, with the loss of some cannon and an entire platoon, killed or prisoner.

[4] After Napoleon's abdication, Guyot was named commander of the 'Royal Corps of Cuirassiers', formerly Grenadiers à Cheval de la Garde Impériale.

Nevertheless, during the Hundred Days, Guyot rallied to Napoleon's cause and he was again given the command of the Guard heavy cavalry division, at the head of which he charged at Waterloo, where he was wounded twice.