Following the outbreak of the Franco-Prussian War on 19 July 1870, on 12 August 1870, Canrobert declined to take command of the Army of the Rhine, petrified by the responsibilities which would ensue. Abandoning the post to Bazaine, Canrobert became an obedient subordinate. He took part in the battles of Sainte-Barbe, Noisseville and Landonchamps. On August 16/18, he commanded the 6th Army Corps and demonstrated distinguished capability at Saint-Privat where he shook three corps of Général von Steinmetz and decimated the 1st Infantry Regiment of the Prussian Guard (). However, due to a mistake in the supply of ammunition and reinforcements, he abandoned his position. He was made prisoner - with Marshal Bazaine - during the surrender of Metz on 28 October 1870. Following several months in captivity, he was liberated and returned to France in March 1871.