<prompt> Bhala ukuqhubeka kwalesi sigaba - Ngo-September 30, i-Gruppe yathuthela enkundleni yezindiza e-Uetersen, indiza imisebenzi yokuzivikela phezu kweGerman Bight. Le yunithi yathutha izikhathi eziningana futhi yayindiza ivikela iReich kusuka e-Esbjerg ngoMeyi 10, 1940, ekuqaleni kweMpi yaseFrance. Ngo-14 May, u-I. Jagd Gruppe wadluliselwa e-Essen-Mülheim ukuze ayosebenza ngokumelene neFrance. NgoMeyi 23, baphinde badluliselwa, kulokhu baya eFerme Montecouvez, inkundla yezindiza eseningizimu yeCambrai. Ezinsukwini ezimbili kamuva, i-I. Jagd Gruppe yanikezwa umsebenzi wokuhlinzeka ngezindiza zokuhamba ngezimoto zaseJalimane ezihambisa kabusha i-4th Army endaweni yaseCambrai. Kulolu hambo, uClausen wabiza i- Armée de lair Potez 63 indiza enezinjini ezimbili eyabhidlizwa. Kulokhu kuhlangana, i-Messerschmitt Bf 109 E yakhe nayo yalimala, okwaholela ekushayweni phansi okuphoqelelwe eduze neCambrai. Ngo-June 15, i-Gruppe yathuthelwa eSaint-Omer, indawo yokuyekisa ukulwa  <response>: yasayinwa ngoJuni 22, kwaqeda iMpi yaseFrance ngoJuni 25. Leli thimba lanikezwa izinsuku ezintathu zokuphumula, abanye abashayeli bezindiza bathunyelwa ekhaya. NgoJuni 30, i-I. Jagd Gruppe yathunyelwa ukuyokweqa indiza yezindiza zaseBristol Blenheim zeRoyal Air Force okwaholela ekulweni eningizimu-ntshonalanga yeSaint-Omer. Kulokhu kuhlangana, uClausen wafuna iBlenheim evela kuNombolo 110 Squadron eyashayiswa phansi, engaqinisekiswanga kodwa yena ngokwakhe wadutshulwa ngeBf 109 E. UClausen wanikezwa i-Iron Cross 1st Class ngoJulayi 4 1940 futhi wakhushulelwa esikhundleni sokuba Oberleutnant u-lieutenant wokuqala ngoFebhuwari 1 1941. Ngalolo suku, uClausen waphinde waqokwa Staffelkapitän umholi weqembu we-1. Staffel of Jagdgeschwader 77 JG 7777th Fighter Wing ngomhlaka 6 Januwari 1942. 