During the French Revolutionary Wars he fought in the Italian campaign of 1796–1797 under Napoleon Bonaparte, leading the cavalry at Lodi and Castiglione.

Born into a noble family from the province of Touraine, Beaumont became a page in the household of King Louis XVI of France on 31 December 1777.

[2] At that time, Beaumont was a brigadier in the 3,090-man 1st Cavalry Division under the overall command of Henri Christian Michel de Stengel.

In April, Beaumont fought in the Montenotte Campaign,[3] in which Stengel was mortally wounded at the Battle of Mondovì.

[5] At the Battle of Lodi on 10 May, Bonaparte directed him to take his cavalry to ford the Adda River and flank the Austrians out of position.

A ford was located 800 meters upstream but it was hard to move significant numbers of horsemen across because the river banks were a tangle of trees.

Though the horsemen were not directly involved, the knowledge that enemy cavalry were crossing the river helped to unnerve the Austrian defenders.

As the French cavalry advance guard approached Crema in a cloud of dust, the observer made out the leading horseman yelling at the Austrian stragglers whom he encountered on the road.

[7] At the Battle of Castiglione on 5 August 1796, a powerful redoubt crowned a small hill on the Austrian left flank near the village of Medole.

To take the Monte Medolano position, Bonaparte assigned Beaumont's cavalry, Auguste Marmont's 15 to 18 artillery pieces, and the 4th Line Infantry Demi-Brigade under Jean-Antoine Verdier.

Though the French tried to cut off the retreat of Dagobert Sigmund von Wurmser's army, it was able to escape across the Mincio River.

Moving south along the Lech River to Nordendorf, they turned west and appeared before Franz Xavier Auffenburg's 5,400 Austrians at Wertingen.

[11] Klein's division marched south and west to flank the Austrians, while Beaumont and Trelliard attacked in front.

The formation was attacked with the help of Nicolas Oudinot's infantry division and driven back in increasing confusion.

[13] After the Austrians surrendered at the Battle of Ulm, Napoleon's army pursued a rear guard led by Maximilian, Count of Merveldt to the east.

[14] The next day, 4,000 troops from Merveldt's rear guard under Emmanuel von Schustekh-Herve made a stand at Lambach on the Traun River.

After the Prussian rear guard under Prince Augustus of Prussia became separated from the marching column, Beaumont charged it repeatedly, driving it northward.