Battle Plans
The Supreme Commander of France's army, Maurice Gamelin, like the rest of the French government, was expecting a campaign from the Germans that in the strategic sense would mirror the First World War. The von Schlieffen Plan, Gamelin believed, was to be repeated with a reasonably close degree of accuracy, and even though important parts of the French army in the 1930s had been designed to wage offensive warfare, it would be preferable to confront such a threat defensively, as the French military staff believed its country was not equipped militarily or economically to launch a decisive offensive initially. It would be better to wait until 1941 to fully exploit the combined allied economic superiority over Germany.
To confront the expected German plan - which rested on a move into the Low Countries outflanking the fortified Maginot Line - Gamelin intended to send the best units of the French army along with the British Expeditionary Force north to halt the Germans in the area of the river Dyle east of Brussels until a decisive victory could be achieved with the support of the united British, Belgian, French and Dutch armies. The original German plan closely resembled Gamelin's expectations.
Von Manstein and Case Yello
The crash in Belgium of a light plane carrying two German officers with a copy of the then-current invasion plan forced Hitler to scrap the plan and search for an original alternative. The final plan for Fall Gelb (Case Yellow) had been suggested by General Erich von Manstein, then serving as Chief of Staff to Gerd von Rundstedt, but had been initially rejected by the German General Staff. It proposed a deep penetration further south of the original route, which took advantage of the speed of the unified Panzer divisions to separate and encircle the opposing forces. It had the virtue of being unlikely (from a defensive point of view) as the Ardennes were heavily wooded and implausible as a route for a mechanized invasion. It had the considerable virtue of not having been intercepted by the Allies (for no copies were being carried about) and of being dramatic, which seems to have appealed to Hitler.
Manstein's aggressive plan was to break through the weak Allied centre with overwhelming force, trap the forces to the north in a pocket, and drive on to Paris. The plan benefited from an Allied response close to how they would have responded in the original case; namely, that a large part of French and British strength was drawn north to defend Belgium and Picardy. To help ensure this result, the German Army Group B was still expected to attack Belgium and the Netherlands in order to draw Allied forces eastward into the developing encirclement, as well as obtaining bases for a later attack on Britain.
The Allied general staff and key statesmen, after capturing the original invasion plans, were initially jubilant that they had potentially won a key victory in the war before the campaign was even fought. Contrarily, General Gamelin and Lord Gort, the commander of the British Expeditionary Force, were shaken into realizing that whatever the Germans came up with instead would not be what they had initially expected. More and more Gamelin became convinced that the Germans would try to attempt a breakthrough by concentrating their mechanized forces. They could hardly hope to break the Maginot Line on his right flank or to overcome the allied concentration of forces on the left flank. That only left the centre. But most of the centre was covered by the river Meuse. Tanks were useless in defeating fortified river positions. However at Namur the river made a sharp turn to the east, creating a gap between itself and the river Dyle. This Gembloux Gap, ideal for mechanized warfare, was a very dangerous weak spot. Gamelin decided to concentrate half of his armoured reserves there. Of course the Germans might try to overcome the Meuse position by using infantry. But that could only be achieved by massive artillery support, the build-up of which would give Gamelin ample warning.
"Go forward now and do your duty!"
On 10 May 1940 the German Army launched its western offensive against France and her neighbouring allies. In his Order of the Day, Hitler declares, "Soldiers of the Western Front! The battle which is beginning today will decide the fate of the German nation for the next thousand years. "Go forward now and do your duty!" German forces under the command of General Ewald von Kleist, in accordance with Plan Yellow, attacked through the Ardennes Region. The XIXth Panzer Corps, commanded by General Heinz Guderian, led Group von Kleist through the "impenetrable forest" towards Sedan. On the Belgian/Luxemburg border at Martelange, advance units of the Germany Army encountered their first resistance of the war from the Belgian 4th Company, Chasseurs Ardennais Battalion. After a slight delay at Martelange, the German war machine continued towards Bodange. Using the terrain to their advantage, 5th Company, Chasseurs Ardennais Battalion delayed the German advance for eight hours.
As the German 1st Panzer Division continued west through Belgium, it began to encounter French cavalry (5th LCD) which had been sent forward to delay the Germans. Contact between the two forces occurred on the outskirts of Petitvoir, where the German panzers moved deep into the rear of the French Cavalry and routed them. Belgian infantry regiments and French Light Divisions of the Cavalry (Divisions Légères de Cavalerie) were smashed in the course of action. A rapid German advance combined with a poorly executed French defense allowed the Germans to easily cross the Semois River at Mouzaive. German tanks forded the shallow stream. In addition to the crossings at Mouzaive, the Germans captured Bouillon and began pouring troops across the river less than 15 kilometers from Sedan. Using speed as their security, Guderian's divisions were to manoeuvre along four predetermined routes and reach Sedan before the French High Command identified the German main attack, thereby seizing the initiative away from the French. According to the French high command the Germans could not cross the Meuse in less than ten days. The Germans were there in three and across in four. They arrived at the Meuse River near Sedan the night of May 12/13. On May 13 the Germans forced three crossing near Sedan.
Instead of slowly massing artillery as the French expected, the Germans replaced the need for traditional artillery by using the full might of their bomber force to punch a hole in a narrow sector of the French lines by carpet bombing Sedan was held by the 55. French Infantry Division, a grade “B” reserve division. The forward elements of the 55. ID held their positions through most of the 13, initially repulsing three of the six German crossing attempts; however, the German air attacks had disrupted the French supporting artillery batteries and created an impression among the troops of the 55. ID that they were isolated and abandoned. The combination of the psychological impact of the bombing, the generally slowly expanding German lodgements, deep penetrations by some small German infantry units and the lack of air or artillery support eventually broke down the 55. ID´s resistance and much of the unit went into rout by the evening of May 13/14.
Luftwaffe attacks
The German aerial attack of May 13., with 1215 bomber sorties, the heaviest air bombardment the world had yet witnessed, is considered to have been very effective and key to the successful German river crossing. It was the most effective use of tactical air power yet demonstrated in warfare. The disorder begun at Sedan was spread down the French line by groups of haggard and retreating soldiers. During the night some units in the last prepared defence line at Bulson panicked by the false rumour German tanks were already behind their positions. On May 14th two French tank battalions and supporting infantry from the 71st North African Infantry Division (71e NADI) counter-attacked the German bridgehead without success. The attack was partially repulsed by the first German armour and anti-tank units which had been rushed across the river as quickly as possible at 07.20 hours on pontoon bridges. On May 14th every available Allied light bomber was employed in an attempt to destroy the German pontoon bridges; but, despite incurring the highest single day action losses in the entire history of the British and French air forces, failed to destroy these targets. Despite the failure of numerous quickly planned counterattacks to collapse the German bridgehead, the French Army was successful in re-establishing a continuous defensive position further south; on the west flank of the bridgehead, however, French resistance began to crumble.
The commander of the French Second Army, General Huntzinger, immediately took effective measures to prevent a further weakening of his position. An armoured division (3rd Division Cuirassée de Réserve) and a motorized division blocked further German advances around his flank. However the commander of XIX Panzer Corps, Heinz Guderian, wasn't interested in Huntzinger's flank. Leaving for the moment 10th Panzer Division at the bridgehead to protect it from attacks by 3rd DCR, he moved his 1st and 2nd Panzer divisions sharply to the west on the 15th, undercutting the flank of the French Ninth Army by 40 km and forcing the 102nd Fortress Division to leave its positions that had blocked XVI Panzer Corps at Monthermé. While the French Second Army had been seriously mauled and had rendered itself impotent, now Ninth Army began to disintegrate completely, for in Belgium also its divisions, not having had the time to fortify, had been pushed back from the river by the unrelenting pressure of German infantry, allowing the impetuous Erwin Rommel to break free with his 7. Panzerdivision. A French armoured division (1st DCR) was sent to block him but advancing unexpectedly fast he surprised it while refuelling on the 15th and dispersed it, despite some losses caused by the heavy French tanks.
On the 16th both Guderian and Rommel disobeyed their explicit direct orders to halt in an act of open insubordination against their superiors and moved their divisions many kilometers to the west, as fast as they could push them. Guderian reached Marle, 80 kilometers from Sedan, Rommel crossed the river Sambre at Le Cateau, a hundred kilometers from his bridgehead, Dinant. While nobody knew the whereabouts of Rommel (he had advanced so quickly that he was out of range for radio contact, earning his 7. Panzer Division the nickname Gespenster-Division, "Ghost Division"), an enraged von Kleist flew to Guderian on the morning of the 17th and after a heated argument relieved him of all duties. However, von Rundstedt would have none of it and refused to confirm the order.
Wide Open Flank
The Panzer Corps now slowed their advance considerably but had put themselves in a very vulnerable position. They were stretched out, exhausted and low on fuel; many tanks had broken down. There now was a dangerous gap between them and the infantry. A determined attack by a fresh large mechanized force could have cut them off and wiped them out.
The French high command, however, was reeling from the shock of the sudden offensive and was stung by a sense of defeatism. On the morning of 15 May, French Prime Minister Paul Reynaud telephoned newly minted Prime Minister of the United Kingdom Winston Churchill and said "We have been defeated. We are beaten; we have lost the battle." Churchill, attempting to console Reynaud reminded the Prime Minister of the times the Germans had broken through allied lines in World War I only to be stopped. However, Reynaud was inconsolable.
Churchill flew to Paris on May 16. He immediately recognized the gravity of the situation when he observed that the French government was already burning its archives and preparing for an evacuation of the capital. In a somber meeting with the French commanders, Churchill asked General Gamelin, "Where is the strategic reserve?" which had saved Paris in the First World War. "There is none," Gamelin replied. Later, Churchill described hearing this as the single most shocking moment in his life. Churchill asked Gamelin when and where the general proposed to launch a counterattack against the flanks of the German bulge. Gamelin simply replied "inferiority of numbers, inferiority of equipment, inferiority of methods".
Sedan was under German occupation until the end of August 1944.By 25th August the Free French, under General Le Clerc, had re-captured Paris and by the 30th Patton's Americans were in Sedan and Verdun.
