Quickly named captain of the 4th battalion of Yonne volunteers, within two years he rose to become a chef de bataillon (major) in the 107th Demi-Brigade.

In August 1805, at the start of the War of the Third Coalition, his regiment joined Jacques Desjardin's division of Marshal Charles-Pierre Augereau's VII Corps.

[1] Having a long march from the environs of Brest, Augereau's men missed the bulk of the fighting but managed to trap Franz Jellacic's Austrian division near Lake Constance.

[3] The beginning of the War of the Fourth Coalition saw Habert's 105th Regiment serving in Jacques Lefranc's brigade of Desjardin's VII Corps Division.

[4] At the Battle of Jena on 14 October 1806, Desjardin's division seized the village of Isserstadt, piercing the right-center of the Prussian-Saxon front and rescuing Marshal Michel Ney's advance guard from a precarious situation.

Blinded by the snow, the VII Corps veered to the left of its intended attack axis to strike the Russian center.

Pounded unmercifully by a 70-gun battery and swamped by counterattacking infantry and cavalry, Augereau's soldiers suffered huge losses and the remnants fled.

[1] On 18 February 1808, Habert won promotion to general of brigade[12] and was granted 4,000 francs worth of annual rent from property in the Kingdom of Westphalia.

By early November he transferred again to lead the 2nd Brigade of Maurice Mathieu's division in Marshal Bon-Adrien Jeannot de Moncey's III Corps.

[19] As war with Austria threatened, Napoleon withdrew large forces from Spain, leaving Junot only 15,000 troops to occupy the province of Aragon.

[20] In May, Habert received a rude introduction to guerilla warfare when Colonel Perena led his militia in chasing out the French garrison at Monzón.

Desiring to recapture the town, Habert sent a force consisting of about 1,000 men from his elite companies plus some cuirassiers across the Cinca River downstream from Monzón.

[21] On the day that Habert's elite companies laid down their arms, Louis-Gabriel Suchet arrived to replace Junot in command.

The Battle of Alcañiz on 23 May 1809, Suchet's first action in independent command, was a French defeat at the hands of Joaquín Blake y Joyes.

In this action, the French corps commander detached Laval to protect Saragossa, while Habert led the remainder of the 1st Division.

When the hoped-for troops showed up at 4:00 PM, the French general hurled Habert's infantry and Pierre Watier's cavalry at Blake's right wing.

[28] Having cleared the Ebro valley, Suchet sent Musnier to fight guerillas to the north, while Laval battled the Spanish to the south.

Accordingly, the III Corps commander advanced to the gates of that port city on 6 March, but within four days abandoned the futile blockade and retreated.

[34] Suchet's next assignment was to seize the fortress-city of Tortosa, a strategically important location which controlled the lower Ebro crossing between Barcelona and Valencia.

The III Corps managed to isolate the city, but was unable to begin a formal siege for many months because of the activities of Spanish guerillas and regular armies in both Aragon and Catalonia.

However, Suchet finally got his heavy artillery forward and Marshal Jacques MacDonald arrived with his VII Corps to cover the proposed operation by 10 December.

Suchet pursued siege operations with vigor and on 2 January 1811 secured the surrender of Spanish commander Conde de Alacha Lilli and his garrison, though some managed to escape.

Gathering his men, Habert led a climactic charge against the defenders, breaking all resistance and capturing the Spanish commander Juan Senen de Contreras.

[12] According to a 15 July 1811 return of Suchet's newly named Army of Aragon, Habert's division included 4,433 men in 11 battalions.

Though outnumbered two-to-one, the French quickly routed Blake's left flank units, but the Spanish center and right fought stubbornly.

Suchet planned a double envelopment, with the greater part of his forces massed inland to cut behind Blake's left flank.

In the Siege of Valencia, Habert carried out his assignment, scattering José Obispo's troops on the right, while Suchet overran the Spanish left.

In that conflict, Suchet sent Louis-Benoit Robert's division to attack the left flank of John Murray, 8th Baronet's Anglo-Spanish army.

When a spy reported news of Napoleon's abdication on 19 April, Habert made his soldiers swear allegiance to the now-deposed emperor.

The next day, when the Frenchman returned with a British naval officer to work out the details of the French evacuation of Barcelona, Habert raged against the colonel, calling him a "traitor", and had to be restrained by his staff.