Kammala jumla mai zuwa: An nada Klein a matsayin janar na sashen a 1799 kuma ya haye Rhine a Kehl a cikin sojojin Jean-Baptiste Jourdans na Danube. Ya umurci gefen dama na Garkuwar Garkuwar, a karkashin umurnin François Joseph Lefebvre. Umurninsa ya hada da 4th da 5th Hussar Regiments, 17th Dragoons, 1st "Chasseurs à cheval", wani rukunin doki mai haske, kamfanoni biyu na doki, biyu na bindigogi, da kuma kamfanin masu sabawa. A cikin
Yaƙin Ostrach, sojojin doki na Klein sun taimaka wajen tabbatar da ƙauyen Hosskirch, wani muhimmin matsayi mai mahimmanci, kafin haɗin kai. Bayan asarar Faransa a Ostrach da kuma yakin Stockach na gaba, Jourdan ya ba da umarnin janyewa gaba daya zuwa Black Forest. Rundunar sojan doki da kuma mafi yawan bangarorin Klein sun haye duwatsu kuma sun yi kusa da Offenburg, inda dawakai zasu iya samun abinci mafi kyau. Duk da ja da baya da aka tsara da kuma wurare masu aminci a gefen yamma na Black Forest, sojojin sun kasance cikin rikici. Jourdan ya sanya shugaban ma'aikatansa Jean Augustin Ernouf a matsayin kwamandan wucin gadi kuma ya tafi Paris don yin gunaguni game da yanayin sojojinsa, kayan aikinsa da kayan aikinsa. Da'a a cikin sahu ya rushe. Yawancin janar-janar sun bar mukaman su, ban da Pierre Marie Barthélemy Ferino, Joseph Souham, Dominique Vandamme da Klein. A watan Mayu, Andre Massena ya karbi umarnin duka rundunar sojojin Danube da rundunar sojojin Helvetia; Klein ya shiga Massena kusa da Zurich.