War of the Fourth Coalition
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. 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.