Kesselring was responsible for all air force units in northern Germany, Netherlands, Belgium and north-eastern France while Sperrle was in control of forces in northern and western France. "Luftflotte" 3 was assigned Alfred Keller's "Fliegerkorps" IV, based in Brittany, Richthofen's "Fliegerkorps" VIII in the Cherbourg region, and Greim's "Fliegerkorps" V in the Seine area—precise boundaries between the air corps are not known. The entire bomber strength of Sperrle's air fleet was reserved for night bombing. Sperrle's command did not begin large-scale daylight attacks until the last week of September.