Napoleon promoted Sahuc to "général de division" on 4 January 1806. He went on to serve as commander of the 2,600-strong 4th Dragoon Division during the War of the Fourth Coalition. The division included the 17th and 27th Dragoons in the 1st Brigade, the 18th and 19th Dragoons in the 2nd Brigade, and the 15th and 25th Dragoons in the 3rd Brigade. Laplanche led the 2nd Brigade, while the other two brigadiers are not given in the sources. His troopers missed the Battle of Jena-Auerstadt because he marched with Marshal Jean-Baptiste Bernadotte's I Corps. After the battle his division joined Marshal Nicolas Soult's IV Corps for the pursuit. On 1 November his division was at Rathenow moving north to attack Gebhard von Blücher. His division's strength at this time was estimated at 2,550. On 6 November, Sahuc was present with Soult and Marshal Joachim Murat in the Battle of Lübeck where he was at the southeast gate. Once the French seized the gate, the cavalry burst into the streets and helped capture the "Owstein" Infantry Regiment No. 7. On 25 January, he was present at the Battle of Mohrungen with the 1st and 2nd Brigades. Napoleon appointed him a "comte de l'empire" in 1808.