During the plot to assassinate Hitler of July 20, 1944, together with the top security man in Paris, SS-Gruppenführer Carl Oberg, he was arrested by Army troops under the command of Paris military governor, General Carl-Heinrich von Stülpnagel. He was released after the coup collapsed. Following the liberation of Paris, Knochen was transferred to the 1st SS Division Leibstandarte SS Adolf Hitler and he was degraded to the rank of SS-Grenadier.
