The Germans succeeded in crushing the French because of the excellence of their operational method:
An observer standing in the midst of the French positions on the heights of La Marfée can clearly make out the crossing points across the Meuse River seized by German infantry on the afternoon of 13 May 1940. The day was bright and cloudless. The French held the commanding heights in strength. Their two hundred guns ranged the ground over which German columns inched their way to assembly areas on the east bank. Yet, the crossing succeeded. Within four hours the 1st Rifle Regiment, supported by Infantry Regiment Grossdeutschland, had crossed the river in strength and ruptured French defenses irreparably. Over the course of the evening, French troops, who held most of the tactical cards, dissolved in panic. In one of those rare moments of cataclysmic impact, a single afternoon’s combat sufficed to open the door to the collapse of the most respected army in the world. The result sealed the fate of the Third Republic.
How could it have happened? Any student of tactics knows that a river crossing against a defended shore is the most difficult of all tactical maneuvers. In such a maneuver, the assaulting side requires overwhelming superiority in firepower and mobility. Yet the Germans had neither. Historians have tended to ascribe the German success to superiority in mechanized warfare. In fact, the critical assault that broke the back of French resistance resulted from the efforts of infantry and combat engineers paddling across the Meuse in rubber boats. The battle culminated in the Wehrmacht’s favor 12 hours before German engineers completed the bridges necessary to carry German armor across.
The Germans succeeded because of the excellence of their operational method – one that played out on the battlefield like a superbly orchestrated symphony. The instruments of blitzkrieg–tactical aircraft, tanks, infantry, sappers, and artillery – each added their own unique harmonic at the right time and in proper balance. They managed to balance the brute strength and psychological intimidation offered by firepower with the speed and physical paralysis provided by rapid movement. This fusion of fire and maneuver resulted in a seamless, unrelenting offensive that made the German assault on Sedan so overwhelmingly decisive. The German success was a triumph, not of overwhelming mass or firepower, but of both applied in harmony using intellect, foresight, imagination and will.
Victory in France had its roots in Germany’s defeat in World War I. Decades of introspection and disciplined study during the inter war years taught the Germans a crucial lesson about the relationship between technology and the nature of war. Modern rifled weapons had upset the balance between the ability of armies to prepare the attack by fire and their ability to use maneuver against the enemy’s vulnerable points. The battlefield had become so vast and lethal that soldiers attacking on foot could no longer cross no-man’s-land with sufficient strength intact to achieve decisive results
What the Germans understood in developing their doctrine was that, given the dispersion of troops, confusion, and chaos characterizing modern warfare, top-down control was no longer in the cards. It worked for Napoleon because he could see virtually the entire battlefield at Austerlitz.
But it was no longer a possibility on a battlefield where not only distance but the very violence and confusion of modern war separated soldiers and units. Troops now had to understand the objective and then, as the operation unfolded, adapt their responses to the tactical situation as it existed. Above all they must not wait for their commanders to tell them what to do. Rather, depending on circumstances, they had to act in accordance with their training, intuition, and understanding of the immediate situation. The balance and harmony between maneuver and fire remained the essential imperative of maneuver warfare through the remainder of the machine age.
Not only German offensive capability was superior but their defensive capability superior too when the bridgehead established. Allied aircraft massed to destroy the river crossing with bombing shot down by the anti-aircraft artillery of the German. What the German Luftwaffe was able to do the allied air force was not.
Some German soldiers later said (of the whole French conquest) that the French soldiers seemed to be looking for ways to surrender.