French resistance could claim its origin in Charles de Gaulle’s Appeal of June 18 on the BBC where he proclaimed that the war was not over. Marshal Philippe Pétain had already signed the armistice treaty and the formation of Vichy France government had begun. De Gaulle also became a de facto leader of Free France. First acts of resistance were organized by secondary school students on 14 July and 11 November 1940. Also, sabotage actions started, as well as occupation strikes by workers – for instance, miners in Nord and Pas-de-Calais went on strike from May 27, 1941 to June 8, 1941. Students protested during meetings with followers of Pétain. In the opinion of some French historians, armed resistance begun on 21 August 1941 when members of youthful battalions Pierre Georges and Gilbert Brustlein killed aspirant of kriegsmarine Alfons Moser.