The Battle of France (French: bataille de France; 10 May – 25 June 1940), also known as the Fall of France, during the Second World War was the German invasion of the Low Countries (Belgium, Luxembourg and the Netherlands) and France. The plan for the invasion of the Low Countries and France was called Fall Gelb (Case Yellow or the Manstein plan). Fall Rot (Case Red) was planned to finish off the French and British after the evacuation at Dunkirk. The Low Countries and France were defeated and occupied by Axis troops down to the Demarcation line.
On 3 September 1939, France and Britain declared war on Nazi Germany, over the German invasion of Poland on 1 September. In early September 1939, the French army began the limited Saar Offensive but by mid-October had withdrawn to the start line.