When the triumphant German Army marched through Paris on 14 June 1940, it added the final humiliation to an already shocked and defeated French nation. The unprecedented speed with which Germany defeated France in 1940 sent shock waves around the world. The first-rate military power had been completely defeated in just six weeks. .
In September of 1939, the French waited for the expected blow to come. While the German army was fully occupied in crushing Poland, the French launched a minor offensive into the Saarland, but the French did not advance beyond the range of the guns in their Maginot Line forts. After Poland was defeated, the troops returned to the safety of the forts, and both sides settled into what became known as the Phoney War. By May of 1940, the Allies looked to be as strong as the Germans, both in manpower and equipment. The total Anglo-French force amounted to 2,500,000 men, which was slightly more than the German army fielded. The allies also outnumbered the Germans in armor: while the French and British possessed 3500 tanks, the German Army could only muster 2570. In the air, however, the Germans outnumbered the Allies by nearly 1000 aircraft, and this superiority was to be critical during the forthcoming campaign. It was in doctrine, organization and faith in themselves that the French were defective. Their methods were outmoded and their gunnery inferior: inequalities, which placed their tanks at a severe disadvantage to the Germans in almost any confrontation. While the French Army continued to rely on doctrine, weapons, and tactics more suited to World War I, the German Army was now confident in its new weapons, doctrine and training. The German military strategy of using of fast-moving tanks, with motorized infantry and artillery supported by dive-bombers and concentrating on one part of the enemy sector became known as Blitzkrieg.
Gamelin, the French Commander-in-Chief, relied on plans to repel a German invasion of France, which had been discussed for many years.