After the fall of Poland, in 1939, Germany began making invasion plans for the attack on France. The original plan resembled the Schlieffien Plan attempted by the Germans in WWI, but a leak in information, led Germany to develop a new plan, which involved invading from further south, cutting through the Ardennes, and surrounding the Allied forces, who’s strategy was based on the defense of the Low Countries, and Northern France. On the French border, the Allies felt a false sense of confidence from the Maginot Line and were acting on war strategies developed in the First World War. Equipment was not ready, timelines were inaccurate, and tanks were divided out between infantry instead of being massed together.
When the first attacks began, Germany launched a feint at Belgium, making the Allies believe that Germany was following their original strategy. The Allies immediately sent troops to the Dutch border without proper planning towards food and supplies. When troops reached their destination, their resources were already exhausted.
As light skirmishes took place in the Dutch territories, the bulk of the Germans moved through the lightly defended Ardennes relatively unopposed.
As the German army neared Sedan, at the river Meuse they came into conflict with divisions of the French army. Though neither side was prepared for the attack, Germany advanced across the river, using bombers to make up for the lack of ready artillery. The attack worked incredibly well, creating a detrimental physiological feeling of isolation in the French reservists, allowing Germany to successfully complete three out of four crossings, laying the way for the drive towards France. Following French counterattacks were of very little benefit; retreating French troops arrived at later points along the line spreading disorder, paranoia, and fear of the German armies, among Allied troops.
After many other small skirmishes and failed counterattacks the French morale had severely begun to crumble. Shocked by the superior efficiency, speed, and tactics of the Blitzkrieg, the French government was already admitting defeat, and even burning the cities archives in preparation for the evacuation of Paris. The situation was going in a downward spiral.
Another source of chaos erupted with the dismissal of the French supreme commander General Gamelin. He was replaced with General Weygand, who worked to reorganize the French command, but due to the disorder, the French resistance meetings took much longer than expected, delaying any decisive action for three days. If these delays had not occurred, the Allied forces would have stood a fair chance at retaking some lost ground.
All at the same time, the German forces were exhausted, with many mechanical failures plaguing their tanks, and lacking on fuel and food. But due to the great delay in response the Germans had time to refuel, and revitalize for the disorganized counter attacks launched by the Allies.
With the Germans pushing foreword and Allied resistance crumbled, the British forces evacuated at Dunkirk, and France was left alone to defend itself. With few reinforcements left to hold the line, the French army was defeated, and the Nazi’s marched into Paris on June 14, 1940 signaling the Fall of France, and removal of one of the greatest forces of opposition in World War II.
Hitler Tours Paris

The Fall of France in June 1940 sent shockwaves through the Allied resistance, as the Germans did the impossible, and removed one of the greatest forces of opposition from the battle. France fell because of a number of tactical errors and oversights made by both the French military command, and government, which left the Allied forces unprepared, and outmaneuvered in the conflict.
One of the first and main problems that plagued France took place between period of the phony war, and the initial invasions of the Low Countries. France and the other Allies did little to capitalize on the great amount of time the Germans had given them, and prepare a solid defense to counter the upcoming invasion. The Maginot line, which would have been a formidable barrier in WWI, gave the French military command a false sense of security, lulling them into making the minimum preparations to combat the upcoming threat. Another factor which prematurely increased the Allies confidence, leading to a tactical oversight was the capture of the German invasion plans from a downed German fighter. These plans matched the earlier Schefilein plan, leading the Allies into believing the Germans would come through the Liege area, and so they positioned their forces accordingly. At the same time the Germans changed strategies, and came through the Ardennes, achieving superior flanking position allowing them to gain an immediate advantage over the Allies. A final factor involving the low level of Allied preparation came from the poor of training received by both French and British conscripts, which was pitted against Germany, and its high standard of training, leaving Allied troops unfit, and unprepared for the struggle.
The next main problem that led to the Allied defeat was the reliance of Allied Generals on tactics developed in the First World War. The Maginot line is a key example of how the Allied troops failed to change strategies, and adapt to the time period. New weapons and machines of war were slow to be made available, leaving the Allies at a great disadvantage. While the Allied troops advanced at a slower pace, the Germans, with their newly developed Blitzkrieg tactics were moving at a much faster rate, substituting artillery for aircraft, and massing their Panzer Divisions together, creating a fast and efficient force that was able to cut through the disorganized Allied infantry. The reliance of outdated tactics and equipment left the Allies vulnerable, allowing the Germans to gain the upper hand, and make a fast advance into France.
The final reason why France fell so quickly is related to the horrible morale suffered by the troops, as they endured defeat after defeat, with few gains. The government of France was burning their archives, in preparation for the occupation of Paris, when the German troops were still weeks away from the capital. The French Premier was admitting defeat. The mood was the same throughout the rest of France, especially in the military. Troops were suffering from a sense of defeat, while the military command was in chaos, spawned by the relief of General Gamelin, and his replacement by General Weygand. This combination of low morale, and chaos in the military prevented more then one opportunity for the Allies to make a decisive counter attack, when the Germans were at their weakest, giving them a fighting chance in the struggle. With these factors surrounding the conflict, the Allied forces were mentally in no shape to conduct the battle ahead of them, and consequently were unable to hold off the Germans, eventually leading to the fall of France.

From the beginning of the conflict, France and the other Allied powers were unprepared for the upcoming battle, drawing a false sense of confidence from factors such as the Maginot line, and captured enemy battle plans. Troops were poorly trained, and equipment was in short supply, while the Generals began making battle plans better designed to fight WWI. Germany on the other hand was an advanced military power, and with the lightning tactics of the Blitzkrieg, better equipment, and preparation, they had a critical advantage over the Allied forces. As Germany made a fast drive into France, retreating Allied troops were constantly subject to defeat, dealing a crippling blow on the troop’s morale, as well as the morale of the French civilians. Matters were at their worst with the change in leadership of the French military command, leaving the army in chaos and confusion. With all these factors considered, the Allied military was not ready to conduct the war ahead of them, which led to the defeat of France in just over six weeks, and the elimination of one of the greatest forces of opposition in WWII.