Rubuta ci gaba don wannan sakin layi - Komawa Turai, amsawa ga wani abin da ya dace da abin da ya faru daga Chancellor Bismarck, majalisar dokokin Faransa ta 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 yakin Sedan ya kama sannan ya sake kama Bazeilles.
Na daga Royal Bavarian Corps karkashin umurnin Janar von der Thann.