In May and June 1794, Charbonnier and Jacques Desjardin jointly led an army that tried three times to establish a foothold on the north bank of the Sambre River.

Soon appointed captain of a company in the 1st Nièvre Volunteer Battalion, he rose in rank to chef de bataillon (major) by the start of 1792.

[8] Opposite the French army were 27,000 Habsburg Austrian and Dutch soldiers led by Franz Wenzel, Graf von Kaunitz-Rietberg.

The Coalition troops were strung out from west to east, with 5,000 near Dinant, 2,000 at Florennes, 2,000 at Boussu-lez-Walcourt, 5,000 at Beaumont, 2,000 at Erquelinnes, 10,000 at Bettignies and garrisons at Namur and Charleroi.

In early April, the commander of the Army of the North Jean-Charles Pichegru directed Charbonnier to take position west of Philippeville.

[12] On 30 April 1794, the Coalition army under Prince Josias of Saxe-Coburg-Saalfeld successfully concluded the Siege of Landrecies.

Pichegru with 70,000 troops of the left wing was directed to capture Ypres and Tournai, while Jacques Ferrand and 24,000 soldiers held the center near Guise and Maubeuge.

[14] Charbonnier received his orders on 6 May and immediately held a conference with Desjardin, François Séverin Marceau-Desgraviers and their chiefs of staff where they drew up plans for the offensive.

[16] In preparation, Charbonnier divided his 17,000-man field force into two divisions under Jacob and Marceau plus an independent detachment under Claude Vezú.

[17] For his part, Desjardin commanded three divisions, his own and those of Éloi Laurent Despeaux and Jacques Fromentin plus an advanced guard under Guillaume Philibert Duhesme.

In the Battle of Grandreng on 13 May, Muller and Despeaux assaulted Kaunitz's right flank, Fromentin attacked his center and the garrison of Maubeuge mounted a diversion.

[24] On 6 May two representatives on mission had written a letter to the Committee of Public Safety describing Charbonnier as incompetent and requesting a more experienced commander.

"[14] Alarmed by the panic that seized some French units on 13 May, representatives en mission Louis Antoine de Saint-Just and Philippe-Francois-Joseph Le Bas published an order promising death to any soldier who malingered or showed cowardice.

In an attempt to unify the command structure Pichegru issued an order that called the Sambre force a single corps.

To concert the force's actions, he created a council composed of Charbonnier, Desjardin, Jean Baptiste Kléber and Barthélemy Louis Joseph Schérer.

Kléber suggested using Mayer's unengaged division near Bonne-Espérance to launch a counterattack on Kaunitz's left flank.

But since Mayer belonged to the Army of the Ardennes, Desjardin declined to give the general a direct order.

There is evidence from his correspondence that Charbonnier was jealous of his authority as army commander-in-chief and was reluctant to follow Pichegru's instructions.

A council of war the following day determined to send Kléber with 15,000 men on a raid north toward Nivelles.

[33] The French generals completely ignored Kaunitz who formed his troops into five attack columns and a Dutch reserve.

On the French left, the Austrians quickly overran Erquelinnes and forced the divisions of Anne Charles Basset Montaigu (formerly Despeaux's) and Muller to recross the river to Solre-le-Sambre.

[35] Hearing the guns, Kléber turned back from his mission and managed to block the Coalition pursuit long enough for Mayer's division to escape.

[20] Another authority estimated that the French lost 3,000 killed and wounded while the Coalition captured 2,400 men, 32 guns and three colors in the debacle.

The generals hoped for some time to reorganize and supply the soldiers with food and shoes, but during the meeting Saint-Just cut off all further discussion by declaring, "Tomorrow you will make a victory for the Republic: choose between a siege or a battle".

Marceau's troops went on strike and refused to attack, but the Austrians were unaware of this and evacuated the La Tombe camp that night.

On 30 May, Charleroi was completely invested by a ring of French troops and Mayer's division entrusted with the siege operations.

–Ramsay Weston Phipps[14] Meanwhile, Kaunitz was replaced by the Hereditary Prince William of Orange and the Coalition army was reinforced to 35,000 troops on 1 June.

Mayer's division was nearly trapped between the successful Coalition attackers and the garrison of Charleroi, but managed to escape thanks to Marceau who held the bridge at Marchienne-au-Pont.