Marchand served under Ney again in Marshal André Masséna's third invasion of Portugal in 1810. He fought at the Siege of Ciudad Rodrigo from 26 April ro 9 July 1810 and the Siege of Almeida from 25 July to 27 August. On 15 September, Marchand's 1st Division consisted of Maucune's 1st Brigade, the 6th Light and 69th Line, and Marcognet's 2nd Brigade, the 39th and 76th Line. There were 6,457 men and 214 officers in the division. At the Battle of Bussaco on 27 September, Louis Henri Loison's division led the attack up the main road toward to top of the ridge. Fighting its way through knots of British and Portuguese skirmishers, it was met at the crest by British infantry and artillery and defeated. Too late to support Loison, one of Marchand's brigades neared the top of the ridge. Because of hostile artillery fire it strayed to the left of the road. Marchand's attack was beaten by Denis Pack's Portuguese brigade. His division suffered the loss of 1,173 men while Loison's division sustained 1,252 casualties.