Beaumont led the 3rd Dragoon Division at the Battle of Jena on 14 October 1806 in the War of the Fourth Coalition. His division was one of the three present with Marshal Joachim Murat at the Capitulation of Erfurt. The 3rd Division included the 5th, 8th, 12th, 16th, 19th, and 21st Dragoon Regiments. He was active in the pursuit of Prince Hohenlohe's Prussian corps. He was present in the action of Zehdenick on 26 October. Beaumont played a prominent role at the Battle of Prenzlau on 28 October. After the Prussian rear guard under Prince Augustus of Prussia became separated from the marching column, Beaumont charged it repeatedly, driving it northward. He finally pinned the rear guard against the Uecker River, forcing it to surrender. Hohenlohe capitulated with his main body soon afterward. He was present at the Battle of Czarnowo on 23 December 1806.