On 17 April he presented himself before this position, whilst his right (linked to a division of the Army of the Rhine) attacked the Austrians at Merzig near Trier.

Jourdan was forced to demote Lefebvre so as not to leave him exposed to a bombardment that would be as murderous as it would be useless, and the affair was postponed until the following day.

On 18 April Lefebvre, Morlot and Hatry made a frontal assault on the Austrian redoubts, but at the moment they had formed up for a bayonet charge, the division under Championnet, which had turned the enemy left in taking the heights of Toernich, threw the Austrian ranks into such disorder that they fled on the road to Luxembourg.

The left of the Army of the Moselle set up base in Arlon, but Beaulieu returned in force on 29 April and surprised Hatry and Championnet who, at their turn, had to retreat in disorder to Aubange and Longwy.

Faced with Jourdan's advance, he then retired to a defensive position at Ardoy, across the river Meuse from Namur, via Dinant.