Charles Marie joined his father's 1743 campaign in the War of Austrian Succession, first as lieutenant-colonel and later as colonel of the second Walloon Infantry Regiment, which he had raised personally. He commanded this regiment in the 1744 and 1745 campaigns, until he became colonel of the Baden-Baden Regiment. One year later he became major general. In 1748, he played an important role in the defence of Maastricht against the French.