Stab./KG 55 began operations on 10 May in the Lorraine region of France, which would include missions over Nancy, Toul and Epinal. In the first day of action the "Geschwader" did not suffer any casualties. II. and III./KG 55 attacked Nancy-Essey Airport which was heavily damaged. I./KG 55 attacked Toul-Croix de Metz Airfield. I./KG 55 moved to Baltringen in the evening and flew a long-range operation against rail depots in Orléans on 11 May. II./KG 55 flew attacks against similar targets but included bombing rail and bridge targets around Châteaudun on 12 May. KG 55 flew attacks against 38 airfields from 11 to 13 May. Hugo Sperrle, commanding "Luftflotte" 3, claimed 100 Allied aircraft on the ground in these operation and another 100–150 in hangars. A second operation hit the railway of Rethel. Stab./KG 55 attacked the Châteaudun Air Base and supported German army advances at Charleville-Mézières and the Battle at Sedan. From 11 May–2 June it flew operations against Châteauroux-Déols Air Base, Orleans, Soissons and Lyon – Mont Verdun Air Bases.