Pedzisa mutsara unotevera: Musi wa30 September, "Gruppe" yakaenda kunhandare yendege paUetersen, ichibhururuka mishoni dzekudzivirira pamusoro peGerman Bight. The chikwata rakatamisirwa kakawanda uye akanga achibhururuka mukudzivirira Reich kubva Esbjerg musi 10 May 1940, kutanga Hondo France. Pana 14 May, I. ((Jagd) "Gruppe" yakatamiswa kuEssen-Mülheim nokuda kwemabasa anorwisana neFrance. Musi waMay 23, vakatamirazve, panguva ino kuFerme Montecouvez, nhandare yendege iri kumaodzanyemba kweCambrai. Mazuva maviri gare gare, I. ((Jagd) "Gruppe" akapiwa basa rekupa varwi vanoperekedza vatakuri veGermany vachidzorera mauto e4 pedyo neCambrai. Pachinangwa ichi, Clausen akati "Armée de l'air" Potez 63 ndege mbiri-engined yakadonha. Mukurwisana uku, Messerschmitt Bf 109 E yake yakakuvadzwawo, zvichiguma nokumanikidzwa kumhara pedyo neCambrai. Pana 15 June, I. ((Jagd) "Gruppe" yakatamiswa kuSaint-Omer,
chibvumirano chokurwisana chakasainwa musi wa 22 June, kuchigumisa Hondo yeFrance musi wa 25 June. Boka racho rakapiwa mazuva matatu okuzorora, vamwe vatyairi vendege vakatumirwa kumba kuzororo. Musi wa 30 Chikumi, I. ((Jagd) "Gruppe" yakamhanya kunopinda ndege yeRoyal Air Force Bristol Blenheim vabhomba zvichikonzera kurwa kumaodzanyemba kwakadziva kumadokero kweSaint-Omer. In kuonana ichi, Clausen akati Blenheim kubva No. 110 Squadron akapfura pasi iyo haina kusimbiswa asi akanga pachake akapfura pasi ake Bf 109 E. Clausen akanga paakavapa Iron Cross 1st Kirasi () musi 4 July 1940 uye akasimudzirwa kuti "Oberleutnant" (wechipiri lieutenant) musi 1 February 1941. Zuva iroro, Clausen akagadzwawo "Staffelkapitän" (mutungamiri wechikwata) we1. ((Jagd) "Staffel" weLG 2, chikwata ichi chakava 1. "Staffel" we "Jagdgeschwader" 77 (JG 77<unk>77th Fighter Wing) musi wa 6 Ndira 1942.