 Nyorai kupfuurira kweiyi ndima - Pashure pokudzokera kuFrance, Cassagne akapiwa basa rokudzivirira Maubeuge kusvikira muna 1804 paakatumirwa kuBruges. Akava mukuru weLegion of Honor musi wa 4 June 1804. Hurumende yake yakaiswa muchikamu chaCharles-Étienne Gudin de La Sablonnière mu III Corps. Akarwa muHondo yeTatu yeMubatanidzwa muHumambo hweAustria muna 1805 uye muHumambo hwePrussia nePoland muna 1806-1807. Muhondo yeAuerstadt, 25th Line Infantry Regiment yakatora zvombo zviviri kubva kuvaPrussian uye Cassagne akarohwa nechombo kumeso uye bhiza rakaurayiwa pasi pake. 25th Line yakarwa muhondo yePułtusk musi wa 26 Zvita 1806 uye muhondo yeEylaumusi wa8 February 1807. Cassagne akasimudzirwa kuva brigade general musi wa 7 Chikumi 1807. Napoleon akamukwidziridza kukudzwa kwaBaron weHumambo musi wa 8 Kurume 1808. 