Kammala jumla mai zuwa: Yakin Faransa, mamayewar Jamus na Faransa da Low Countries, ya fara ne a ranar 10 ga Mayu, 1940. A ranar 18 ga Mayu, 1940, ya shiga cikin yaƙin iska tare da jiragen saman Curtiss P-36 Hawk guda takwas na Faransa kuma an harbe shi a yammacin Rethel. Mai yiwuwa wanda ya yi nasara shi ne Camille Plubeau. Wilcke ya tsere kuma aka kama shi a matsayin fursunonin yaki. Bayan da
yarjejeniya tare da Faransa, shi da Mölders, wanda shi ma ya kasance fursunonin yaki, ya koma ƙungiyar a ranar 30 ga Yuni, 1940. An gabatar da Wilcke zuwa "Hauptmann" a rana mai zuwa kuma ya sake zama kwamandan 7. "Stafell" (Aikin Ƙari) A ranar 11 ga Yuli, 1940, an ba shi lambar yabo ta Iron Cross 1st Class ().