On the second invasion of Bohemia, Moulin's regiment was part of the first corps, which, during the summer of 1744, laid a successful siege to Prague. On 14 November 1744, he was promoted to the rank of lieutenant general. On 1 May 1745, the King, with the command of a corps of 10 grenadier battalions and 40 squadrons of cavalry, ordered him to protect Bohemian mountain passes. He evaded the main Austrian army and joined the Prussian main army in time for the Battle of Hohenfriedberg on 4 June 1745. Subsequently, he was received as a Knight of the Black Eagle Order.