At the time he used the false name "Monsieur Schumann" and attempted to develop contacts with the Parti communiste français.
Kühne fought in the battles of 7–8 April 1944 at Saint-Étienne-Vallée-Française (Lozère), where the German maquis destroyed a patrol of the Feldgendarmerie and in an ambush against the Waffen SS on 5 June 1944 at La Rivière.
When the various elements of the German maquis reformed at the Plan de Fontmort, a high place of resistance of the Camisards, Kühne took command.
He also fought in the battles for French liberation, welcoming deserters from the Wehrmacht (particularly Armenians) in the Mende region.
Kühne seems not to have participated in the liberation of Nîmes in person, or in the parade of 4 September (unlike other German anti-fascists).