His career then stagnated until the War of the Second Coalition when he led a brigade in Italy at Verona, Magnano, Cassano, Bassignana where he was wounded, and Novi.

After being released, he served in the 1809 Invasion of Portugal but was later detached to lead a column of dismounted cavalrymen back to France.

During the War of the Sixth Coalition he commanded a division under Eugène de Beauharnais in Italy, fighting at the battles of Feistritz, Bassano, Caldiero, and the Mincio.

[1] At the Battle of Boulou on 30 April 1794, French army commander Jacques François Dugommier launched a heavy attack on the Spanish right center, bending back the enemy lines.

The following day, the French cracked the Spanish defenses and the cavalry commander, André de la Barre ordered Quesnel to take his brigade and harass the retreat of one enemy column.

His troopers herded the Spanish into a deadly ambush in the Le Perthus Pass and their foes were cut to pieces, losing their artillery and wagon train.

After the Coup of 18 Fructidor on 4 September 1797, Quesnel was denounced by the local Executive Commissioner for having connections with persons with counter-revolutionary leanings.

However, Quesnel had come under suspicion because he married a noblewoman and socialized with persons believed to be loyal to the pre-coup government.

Generals Pierre Augereau and Louis Lemoine both attested to his good conduct while fighting against the Spanish and the Vendée rebels.

He was named governor of Porto (Oporto) and Entre-Douro-e-Minho Province, with authority over the Spanish troops occupying the region.

[1] On 6 June 1808 news of the Dos de Mayo Uprising reached Porto and Spanish General Belesta seized Quesnel, his staff, and his 30-man dragoon escort as prisoners.

After urging the Portuguese to revolt against the French, Belesta immediately marched back to Spain with his 6,000 soldiers and his prisoners.

[1] On 10 April 1811, Spanish guerillas under Francesc Rovira i Sala seized Sant Ferran Castle, throwing the French position in Catalonia into chaos.

With this force, plus large reinforcements under Louis Auguste Marchand Plauzonne, the French began the Siege of Figueras.

The besiegers repelled a Spanish relief attempt on 3 May but the operation tied up the VII Corps for the entire summer.

On 6 September, Grenier drubbed Hiller's troops in the Battle of Feistritz and forced them back to the east bank.

[19] As the Army of Italy fell back farther to the Brenta River, Eugene and Grenier found an Austrian column under Christoph Ludwig von Eckhardt in occupation of Bassano, blocking the retreat.

In the Battle of Bassano on 31 October 1813, Grenier attacked Eckhart in three columns and forced the Austrians to scatter into the hills.

The successful operation in the Battle of Caldiero drove back the Austrians and inflicted losses of 1,500 killed and wounded plus 900 men and two cannons captured.

[23] Unhappy with Hiller's performance, the Austrian high command replaced him with Count Heinrich von Bellegarde.

As the Franco-Italians pressed their enemies north toward Valeggio sul Mincio and Borghetto, Eugene sent Quesnel and Rouyer to the left and brought Marcognet into the front line.

[27] After Napoleon's abdication, Quesnel became reconciled to the Bourbons and King Louis XVIII of France awarded him the Order of Saint-Louis.

However, Quesnel rallied to Napoleon during the Hundred Days and was assigned to Marshal Louis-Gabriel Suchet's Army of the Alps.

One source asserted that his death could not have been a suicide because he was held in high regard in military circles and gave no hint that morning that something was wrong.