The Fall of France

France had three frontiers and could only fortify one. The Maginot Line covered the German border properly, and it worked: nothing came through it. The Belgian border could not be fortified because Belgium had declared neutrality in 1936 and would not permit French works or French troops until it was invaded. Between the two lies the Ardennes.

The Ardennes is 100 miles of wooded hills cut by narrow valleys and few roads. French assessments were not that it was impassable; they were that a large mechanised force moving through it would take about nine days to reach the Meuse and would be strung out on the roads while doing it, which would give ample time to react. The assessment of the terrain was right. The assessment of the time was wrong by six days.

Behind the Meuse at Sedan the country opens out into rolling farmland with good roads running west to the sea, and nothing in particular to stop an army that gets across the river. The whole campaign is contained in that sentence.

The Allied plan, Dyle-Breda, moved the best French armies and the entire British Expeditionary Force north-east into Belgium the moment the invasion began, to meet the expected main attack on a line forward of the frontier. It was not stupid: it kept the fighting out of France and joined up with the Belgian and Dutch armies. It also put the best mobile forces at the far end of the hinge, and the hinge was at Sedan.

The German plan had originally been the same as 1914, a wheel through Belgium. Manstein argued for shifting the weight to the Ardennes and cutting behind the Allied armies once they had moved forward. He was moved sideways for pressing it. The plan was adopted in February 1940 after a courier crashed in Belgium carrying the original one.

The deeper failure was not the plan but the machinery. French command worked by written order carried by liaison officer, with a headquarters that had no radio to speak of, on the assumption of a battle that developed over days. The German armoured divisions had a radio in every tank and commanders at the front. By the time a French decision reached the units it was addressed to, it described a situation that had ceased to exist.

France had about 3,250 tanks to Germany's 2,440, and the best of them, the Char B1 bis and the Somua S35, were better armoured and better armed than anything the Germans had. At Stonne and at Hannut French tanks fought German tanks and won.

The difference was in how they were held. French armour was distributed along the front in support of infantry, a few dozen here and there. German armour was concentrated in ten panzer divisions, each with its own infantry, artillery, engineers and, decisively, radio. One side had better tanks; the other had a better idea about what tanks are for.

Around 90,000 French soldiers were killed in six weeks, a rate higher than anything on the Western Front in 1944 and 1945, and about 1.8 million were taken prisoner, many of whom stayed in Germany until 1945. German losses of about 49,000 dead were serious by the standards of 1940 and trivial by the standards of what came later.

The civilian cost is less often counted. Something in the order of six to ten million people left their homes and moved south in the exode of May and June, one of the largest civilian movements in European history, on roads that were bombed and strafed while they were on them.

L. F. Ellis's The War in France and Flanders is the British official history. The French records are at Vincennes and the German at Freiburg. Marc Bloch's L'Étrange Défaite, written by a historian who had served as a staff officer and was shot by the Gestapo in 1944, is still the sharpest single analysis of why it happened.

Julian Jackson's The Fall of France is the best modern account and is the main corrective to the older story of a decadent country that would not fight.