France was invaded and occupied after a disastrous military campaign in May–June 1940. Under the armistice agreement, the country was divided into two zones: an area in the northern half of the country (including Paris) under direct German military occupation and a "Free Zone" in the South ruled by the semi-independent Vichy regime under Marshal Philippe Pétain. Frustration and unrest in both parts led to the emergence of the French Resistance which, by 1942, had become a mass movement.