Kammala wannan jumla: A Turai, da yake amsawa ga wani abin da ya faru daga Bismarck, majalisar dokokin Faransa ta yi zabe don bayyana yakin da Prussia a ranar 19 ga Yuli, 1870. Ƙungiyar Lambert ta sami kanta kusa da Sedan inda kwamandan Faransa Marshal de MacMahon ya yanke shawarar mayar da hankali ga dakarun soja don hana wani shirin da aka yi na Prussian ta hanyar Belgium. A wannan lokacin Lambert yana aiki tare da 2nd Marine Infantry Regiment ("2e Régiment d'Infanterie de Marine") wanda ya kasance wani ɓangare na abin da ake kira Blue Division wanda a cikin jerin hare-haren daji a lokacin yaƙin Sedan ya kama sannan kuma
ya sake kama Bazeilles daga I Royal Bavarian Corps karkashin umurnin Janar von der Thann.