He became a Baron of the Empire on 18 March 1809. In the War of the Fifth Coalition his division of French-allied Germans guarded Napoleon's line of communications. His forces were mauled at Franzensfeste on 4 August 1809 while attempting to suppress the Tyrolean Rebellion. In early 1810 he led a division in Catalonia. In 1813 and 1814, he commanded the 2nd Division in Italy at Caldiero and the Mincio. King Louis XVIII of France appointed him a chevalier of the Order of Saint Louis. He was buried at Barville, Vosges on 10 August 1824. ROUYER is one of the names inscribed under the Arc de Triomphe, on Column 1.