The invasion of western Europe

On 10 May 1940 Hitler ordered the invasion of Luxembourg, Holland and Belgium. Two days later, German troops crossed the border into France. The French were taken by surprise because the German tanks had found a way through the Ardennes forest. They had thought that tanks could not pass through the forest and so only had second rate troops to defend it. The French were forced to retreat right from the start of Hitler's new Blitzkrieg.

The Maginot Line

The French High Command had been certain that the Germans would attack along the French-German border and between 1929 and 1934 they had built a series of underground forts along that border, known as the Maginot Line. France therefore gave little consideration to developing other plans in case the Germans attacked elsewhere.

These forts of the Maginot Line were impressive structures and the French were confident they could hold off the Germans. They may well have done - had the Germans chosen to attack them. The German attack on 12 May came at precisely the point where the Maginot line ended - at Sedan. The Maginot Line proved to be both expensive and useless, and the 30 French divisions that manned it were badly needed elsewhere. Had the French High Command used their excellent tanks in the same way as the Germans, the outcome may have been different. Instead, they spread their tanks thinly over a wide area and they were easily destroyed.

Neil Demarco: The era of the Second World War; Oxford University Press, 1993/2000, page 29