On August 23rd, 1939, as war between France and Germany loomed, a French soldier named Daniel Barlone confided in his diary: “We do not doubt our victory.” When he wrote these words, Germany had not yet invaded Poland, and France had not declared the war that Captain Barlone was certain would favor his homeland. If one were to tell him, however, that less than nine months later the Nazis would launch an attack that defeated France within seven weeks, he would have likely scoffed. But that is exactly what happened.
In the spring of 1940, Germany conquered France in forty-six days, decisively turning World War Two to their advantage. Within the first two weeks of the campaign, the German army outwitted a numerically superior force, which allowed them to carve up a numerically inferior one afterward. Put simply, such a reversal defied steep odds. The Allies didn’t think it could happen. In his own words, the event left Winston Churchill “dumbfounded.” The Nazis didn’t believe they could win so quickly, either. Heinz Guderian, the German general who led the campaign’s decisive thrust, described his own success as a “miracle.” Adolf Hitler also described the outcome as an “absolute miracle.”
How, then, did such a shocking turn of events come to pass? A German defeat of France, much less a rapid one, was far from inevitable. In 1914, Germany threw one of the most powerful armies in human history at France, yet could not, after four years of trench warfare, secure victory. By 1940, France was prepared for another German invasion, with a large well-trained army, an advanced system of fortresses, and secure international alliances. Unfortunately, the Nazis devised a risky plan that exploited fatal weaknesses in the French defenses.
The Gallic Firewall
In June 1919, when the ink on the Treaty of Versailles had barely dried, Ferdinand Foch, who had commanded the French Army in World War I, declared, “This is not a peace. It is an armistice for twenty years.” In other words, many French leaders viewed talk of a ‘war to end all wars’ as merely rhetorical. Given that Germany had defeated France in 1870, and nearly again between 1914-18, it was wise for the country to prepare for another war with its hostile eastern neighbor.
This premonition gave birth to the Maginot Line, a series of fortresses constructed in the 1920s with two purposes in mind. First, to channel any future German invasion through Belgium. By design, the fortresses effectively doomed the prospect of an attack across the Franco-German border. Second, it would free up enough forces to move into Belgium and and establish a line of defense well north of the French border.
The logic seemed sound enough at the time. Germany had invaded France through Belgium in 1914, and came near the outskirts of Paris. Now, France would be ready and able to check a German advance before it reached French soil. This was not so much a plan to refight World War I as much as an effort to avoid its repetition.
A Fortress on the Maginot Line
The French experience of World War I, however, influenced a broader strategy of which the Maginot Line was a central part. World War I had not been won by bravery and clever tactics as much as attrition. French leaders in the 1920s and ‘30s thus reasoned that if they had defeated Germany in one long war of resources, they could win another.France had not won the war of attrition alone, and the men who prepared for the next one were keenly aware of this lesson. Alliances with Britain, Belgium, and, to a lesser extent, the United States formed another, key part of French strategy. While Belgium held an official stance of neutrality, the French army maintained secret contacts with their Belgian counterparts. Also, in 1938, the Prime Minister of France, Edouard Daladier, sought to purchase aircraft from the U.S.
Britain was France’s key ally, and they also assumed France would halt a German invasion. In April, 1938, Winston Churchill described the French army as “the most perfectly trained and faithful mobile force in Europe.” Indeed, at the height of the German invasion, the British Defense Minister, Lord Halifax, wrote: “The one firm rock on which everybody has been willing to build for the past two years was the French army.” British confidence aside, France had been able to extract a substantial commitment from Britain before the outbreak of war. By the spring of 1940, Britain had thirteen divisions and 500 aircraft on the continent.
French defense spending had languished in the 1930s, due to the Great Depression, but by the end of the decade the government had achieved a remarkable feat of rearmament. Despite widespread public sentiment against war, the French defense budget increased from 12.8 billion francs in 1935 to 93.7 billion francs in 1939, with a priority on constructing tanks and airplanes.Public opposition to war changed in early 1939, after Hitler reneged on a promise that Germany would not acquire more territory and annexed Czechoslovakia. When Germany invaded Poland in September of 1939, France declared war, and the nation was by all accounts prepared. They not only had chosen the place to fight, but they had built up the means to do so, and they would not need to fight alone. All France had to do was wait for Germany to make their move.
The Nazis’ rapid defeat of Poland, who possessed the fourth largest army in Europe, shocked outside observers. Maurice Gamelin, the chief of the French army, had expected Poland to hold out for four to six months. But the key elements of the Nazi Blitzkrieg—concentrated formations of tanks working in close coordination with infantry and tactical air support—were not lost on him. To the contrary, Gamelin assumed that the plains of Belgium were best suited to large formations of tanks.
An incident in January 1940 confirmed French assumptions. A German staff officer, Major Hellmuth Reinberger, took off in a small plane from Munster, headed for Cologne. On the way, his pilot got lost and crash landed near Mechelen-sur-Meuse, Belgium. As it happened, Reinberger was carrying a copy of Germany’s plans to invade France, and he was unable to burn them before Belgian soldiers arrested him. The Belgians passed the plans to the French military, who learned that the German army was, in fact, plotting to push through Belgium into northern France, much like they had done in 1914. The key difference was that the Germans also planned to invade the Netherlands.
By May 1940, the Allies had a numerical advantage. The French army boasted 117 divisions, some 2.24 million men. Add to that the 500,000 men of the British Expeditionary Force, as well as a Dutch army numbering 400,000 and a Belgian army of 650,000 men, and the Allies possessed a formidable host of almost 3.8 million soldiers. What is more, the Allied forces possessed 4,204 tanks, and the French air force alone numbered 3,562 combat aircraft.Against this force, Germany planned to throw approximately 3 million men, 2,439 tanks, and 3,578 aircraft. On paper, it was an inferior force, but it was a force that exploited fatal flaws in France’s defense plans.
The Teutonic Gamble
On September 27, 1939, the day Warsaw surrendered, Hitler directed his generals to begin plans for an invasion of France. He wanted it to begin as early as October, and for their part, his generals were horrified by the prospect. Walter von Reichenau, one of Hitler’s most loyal officers described the scheme as “just about criminal.” A few officers considered staging a coup. Their objections were neither moral nor ideological, but purely military. One fourth of the army’s tanks had been destroyed or disabled during the campaign in Poland, and the bulk of the German military was not in a position for a quick transfer to the West. .
Hitler was undeterred by such objections, and he issued a more detailed directive on October 9, which presumed that a confrontation with France would be a long, drawn-out war of attrition. Franz Halder, chief of the army general staff, nominally complied, and began to submit plans he was sure Hitler would reject. Halder’s hope was that he could convince the Führer a hasty invasion of France was a bad idea. These were the plans of which the French learned as a result of the Mechelen incident.
Another German general, however, decided to upset the status quo with his own ambitious proposals. Erich von Manstein was chief of staff to Army Group A, which was to play a subsidiary role in the upcoming invasion. Personally, he was dissatisfied with the plans being developed by the high command. “An outsider was left with the impression,” he wrote in his memoir, “that the [army] leaders considered it doubtful, to say the least, whether any German offensive would be decisively successful.” To him, the existing plans too closely resembled the plan followed in 1914. “I found it humiliating . . . that our generation could do nothing better than repeat an old recipe.”
Manstein saw a fatal weakness in the French defenses: the Ardennes Forest. The dense, hilly Ardennes covers the area where Luxembourg, Belgium, and France converge. Narrow, winding roads comprise its only thoroughfares. When building the Maginot line, the French left the region unfortified because they observed that it was less hospitable to the movement of large armies than the Belgian plains.
To Manstein, a move through Belgium and the Netherlands should only serve to trick the French into thinking Germany was rehashing its plan of 1914. The decisive thrust should go through the Ardennes for the very reason that no one would expect it to come from such an unlikely place. Manstein proposed that if a powerful armored force passed through the Ardennes and then crossed the Meuse river, they would be well positioned to drive to the coast of the English Channel, and cut off the main French force from the rear. Then the best trained and equipped elements of the French army would be surrounded, and foiled by their own strategy.
It is hard to overstate the audacity of this plan. A single German tank division occupied roughly seventy miles of road space. The force necessary for this plan to work would require half of the Nazis’ armored and motorized divisions: more than 1,200 tanks, some 39,000 other vehicles, and approximately 130,000 men. Nose to tail on a single road, such a host would have extended over 600 miles. Crawling through knotted terrain, a force this size would be an enormous, sitting duck for Allied bombers.
Manstein realized his idea might not be greeted warmly by his superiors, so he proposed it incrementally, through seven separate memoranda between October 31, 1939 and January 12, 1940. Franz Halder thought the idea so absurd as to border on insubordination. In response, he transferred Manstein across the country to command a unit that only existed on paper, insuring him, at best, a minor role in the upcoming invasion of France.
Unfortunately for Halder, and France, Manstein found two very powerful advocates. The first was his erstwhile superior Gerd von Rundstedt, who commanded Army Group A, which oversaw the Ardennes sector. Rundstedt was dismayed that initial invasion plans envisioned a relatively small role for his command, and he clamored for more armor units. Manstein’s second advocate was none other than Adolf Hitler.
At the same time as Manstein began publishing his memoranda, Hitler became fixated on the French city of Sedan, which lay on the Meuse river just west of the Ardennes. The Führer’s interest was less strategic than historical. The city had seen the decisive battle of the Franco-Prussian war, which humiliated the French army in 1870, and Hitler was fascinated by the possibility of a repeat performance. When Hitler got wind of Manstein’s plan, he arranged a meeting, where he sat transfixed as Manstein explained it to him.
Hitler’s imprimatur made Manstein’s plan official. Still, it was not popular among the generals assigned to implement it. Fedor von Bock, who would command the push through Belgium and the Netherlands, snorted that the plan “has to bog down if the French haven’t taken leave of their senses.” Even Rundstedt, who was now tasked with the main thrust of the operation, worried that a breakthrough on the Meuse could not be consolidated quickly enough. Another general scoffed, “I don’t think you’ll cross the river in the first place!” Halder, who became a late convert to Manstein’s thinking, was more circumspect: “Even if the operation were to have only a 10 percent chance of success, I would stick with it. For only this can lead to the defeat of the enemy.”
For their largest operation to date, the Nazis adopted a plan that was widely disliked and enormously risky. Allied air forces would somehow need to be oblivious of a large army that stretched for miles as it loped through difficult terrain. Traffic jams would have to be minimal, and supplies needed to be delivered without delay. Once the Germans crossed the Meuse, the French would have to fail to recognize the threat, and not bother to mount a substantial counter attack. In other words, for it to work, practically nothing would have to go wrong.
The Battle of France
On May 10, 1940, the German invasion commenced with frightening speed. Parachutists quickly seized airfields in Holland and disabled Eben Emael, Belgium’s strongest fortress. As Fedor von Bock’s Army group B raced forward, however, Maurice Gamelin felt relieved and confident. It appeared as if everything was going according to plan. He directed Alphonse Georges, the commander of the North-East Front, to move France’s best forces into Belgium to prepare for a decisive battle against von Bock. Georges was also responsible for defending the Ardennes, which he left to two lackluster armies. What he and Gamelin did not realize was that some of the French army’s most untrained, ill-equipped soldiers were about to face Germany’s most formidable units.
Heinz Guderian also felt confident. Charged to lead the vanguard of the strike through the Ardennes, he ordered his officers to “Punch with the fist rather than feel with the fingers.” Going was relatively easy, though by no means trouble free. Blown bridges, sporadic air attacks, traffic jams, and stiffening resistance marred the journey, but did not stop the advance. German soldiers under Guderian’s command rushed headlong across the broken terrain, without sleep. They had been issued 20,000 tablets of Pervitin, a stimulant similar to crystal meth. Along the way, Guderian was also nearly killed by a giant, stuffed boar’s head that fell off the wall of a hotel where he’d set up a temporary headquarters.
German forces reached the Meuse on May 12. On May 13, the Luftwaffe launched a devastating air attack, with some 1,500 planes, against Sedan, which caused a number of French soldiers to flee in panic. By sunset of May 14, the bulk of Guderian’s units—some 600 tanks, 60,000 men, and 22,000 vehicles—had crossed the Meuse and were pushing westward. It was a disaster for the French, and by the time they realized it to be so, it was too late.
Ironically, a French success in Belgium initially blinded them to the threat from the Ardennes. As Guderian reached the Meuse, French tanks harshly rebuffed a German armor attack at the village of Hannut. The next day, the Germans showed their advantage in a counterthrust. Few French tanks were equipped with radios, forcing officers to run from tank to tank to issue orders. Every German tank, on the other hand, had a radio, which enabled efficient coordination.
Despite heavy losses on both sides, the Germans ultimately broke through at Hannut, but the intensity of the fighting convinced Gamelin that Belgium was the primary arena of the fight. On 13 May, Gamelin received word of a “rather serious hitch at Sedan”, but the report was not enough to convince him to change course. French reconnaissance planes had spotted the Nazi force crawling through the Ardennes, prompting the defenders of the Meuse to request more air support, but the high command felt that their planes were better committed elsewhere.
By the next day, as Guderian’s soldiers poured across the Meuse, it became clear the situation was more than just a “hitch.” French forces in the area mounted a counter attack. Fighting was fierce. The village of Stonne, just south of Sedan, changed hands seventeen times, but it was too late. With Guderian rushing westward, the trap had sprung. Distraught and dishonored, General Georges suffered a nervous breakdown. The next day, May 15, Prime Minister Paul Reynaud called Winston Churchill and said, “We are defeated!”
France didn’t sign an armistice until June 22, but the breakthrough on the Meuse sealed the fate of Allied forces in Belgium, and the outcome of the campaign. Heinz Guderian reached the coast of the English Channel on May 20. As if between two great jaws, forty five Allied divisions were encircled in a pocket 120 miles long and 85 miles deep. There was nothing left to do but retreat. The British began to evacuate from Dunkirk on May 26. Belgium capitulated on May 28. A large French force remained in the south of France, but once the Belgian pocket was closed, the Germans enjoyed a numerical advantage of two to one.
Paul Reynaud resigned on June 16, turning control of France to Henri Petain. Petain was a hero of World War I, but he was also hostile to the French republic. He shared the conviction held by a number of officers and civil servants that democracy had made French society too soft. The next day, Petain called for French soldiers to lay down their arms. By the time of the Armistice, 90,000 French soldiers had died in six weeks of fighting. In the following weeks, Petain and his allies in the government would bully their opponents into accepting a dictatorship that was sympathetic to Nazi Germany.
France was not blameless for this debacle. The high command was too rigidly committed to their initial strategy, and thus too slow to react when the situation began to change. The French army should also be faulted for clinging to an obsolete communication system. Orders, typically, needed to be written down before they could be executed, and the high command tended micromanage its officers in the field. On the opposite side, the Germans were more comfortable transmitting orders by radio, and trusted their front-line officers to act on their own initiative. That said, had the Germans acted as the French expected, and focused their main thrust through Belgium instead of the Ardennes, these shortcomings might have been mitigated.
History has not always been kind to France, and this loss spurred the stereotype of French soldiers as cowards. The reality was much more complicated. French soldiers fought well, for the most part; it was their high command, and political leadership, that failed. Even then, Gamelin and his generals made reasonable assumptions based on the information they had at hand. In judicious hindsight, it is not fair to say the French had a particularly bad plan. The Nazis just came up with a better one.
Why Does It Matter?
The collapse of France made Nazi Germany the premier power of Europe, which enabled further conquests. With a free France on Germany’s western border, Hitler would not have been able to invade the Soviet Union. Josef Stalin knew this, and he was only willing to sign a non-aggression pact with Germany because he assumed that an attack on France would exhaust the German army. France’s defeat spurred a frantic attempt to accelerate Soviet rearmament.
More important, removing France from the strategic equation enabled the Nazis’ most ambitious racial designs. France’s defeat, of course, sealed the fate of some 77,000 French Jews. The Soviet Union, though, had loomed large in Hitler’s imagination since, at least, Mein Kampf. Destroying Stalin’s regime and enslaving its people was as much an imperative to him as wiping Judaism from the face of the earth. Poland, regardless, would have suffered terribly. Yet without defeating France, the Nazis would not have been able to murder nearly one and a half million Jews and roughly five million other civilians living in the USSR.
Had the Gallic firewall held, World War II as we know it would have been stopped in its tracks.
 Lloyd Clark, Blitzkrieg: Myth, Reality, and Hitler’s Lightning War: France 1940 (New York: Grove Press, 2016), p. 44.
 Winston Churchill, The Second World War, Volume 2: Their Finest Hour (Boston, MA: Houghton Mifflin Company, 1949), p. 47.
 Karl-Heinz Frieser, The Blitzkrieg Legend: The 1940 Campaign in the West, with John T. Greenwood (Annapolis, MD: Naval Institute Press, 2012), p. 2.
 Richard Overy, The Road to War (London: Penguin Books, 1999), p. 122.
 Julian Jackson, The Fall of France: The Nazi Invasion of 1940 (Oxford, UK: Oxford University Press, 2003), p. 27.
 Jackson, p. 11.
 Jackson, p. 27.
 Philip Nord, France 1940: Defending the Republic (New Haven, CT: Yale University Press, 2015), p. 16.
 Quoted in Eugenia C. Kiesling, Arming Against Hitler: France and the Limits of Military Planning (Lawrence, KS: University of Kansas Press, 1996) , p. 186.
 Jackson, p. 3.
 Frieser, p. 36.
 Frieser, p. 47.
 Nord, p. 34.
 Jackson, p. 75.
 Ernest R. May, Strange Victory: Hitler’s Conquest of France (New York: Hill & Wang, 2000), p. 275.
 May, pp. 315-316.
 Frieser, pp. 35-36.
 Frieser, p. 38.
 Frieser, p. 45.
 Frieser, p. 35.
 Frieser, p. 37.
 Frieser, p. 45.
 Frieser, pp. 55 – 58.
 Clark, pp. 46 – 47.
 Frieser, pp. 61 – 62.
 Erich von Manstein, Lost Victories: The War Memoirs of Hitler’s Most Brilliant General, edited and translated by Anthony G. Powell (Minneapolis, MN: Zenith Press, 2004), p. 93. Manstein’s emphasis.
 Manstein, p. 98.
 Clark, p. 46.
 Clark, p. 67.
 Clark, pp. 60 – 61.
 May, p. 237.
 Frieser, p. 80.
 Clark, p. 64.
 Clark, p. 65.
 Frieser, p. 94.
 May, p 264.
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 Clark, p. 118.
 Clark, p. 123.
 May. p. 422.
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 Clark, 202.
 Frieser, p. 237.
 May, p. 411.
 Nord, p. 91.
 May, p. 413.
 Clark, pp. 257-258.
 Nord, pp. 98-99.
 Nord, p. 99.
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