French airfields lacked effective anti-aircraft protection. In addition, neither the RAF nor the French air force had trained to act in close support for their own ground forces. The Allies had failed to learn this lesson of the Polish campaign, as well as others, such as the Luftwaffe’s skill at ruthless pre-emptive strikes against airfields, and the German army’s ability with sudden armoured thrusts to disorientate the defenders.
After several more postponements, partly due to the Norwegian campaign and partly, in the last few days, to unfavourable weather forecasts, the German invasion in the west was finally set. Friday, 10 May was to be ‘X-Day’. Hitler, with his customary lack of modesty, predicted the ‘ greatest victory in world history’.
Generaloberst von Rundstedt had been reassured by the photo-reconnaissance expert attached to his headquarters that the French defensive positions covering the Meuse were far from finished. Unlike the Luftwaffe, which mounted constant photo-reconnaissance flights over the Allied lines, the French air force refused to send aircraft over German territory. Yet Gamelin’s own military intelligence–the Deuxième Bureau–possessed a remarkably accurate picture of the German order of battle. They had located the bulk of the panzer divisions in the Eifel just beyond the Ardennes and had also discovered that the Germans were interested inthe routes from Sedan towards Abbeville. The French military attaché in Berne, tipped off by the very effective Swiss intelligence service, warned Gamelin’s headquarters on 30 April that the Germans would attack between 8 and 10 May, with Sedan lying on the ‘ principal axis ’ of advance.
Gamelin and other senior French commanders nevertheless remained in a state of denial about the threat. ‘France is not Poland’ was their attitude. General Charles Huntziger , whose Second Army was responsible for the Sedan sector, had only three third-rate divisions on that part of the front. He knew how unprepared and unenthusiastic his reservists were for the fight. Huntziger begged Gamelin for four more divisions because his defences were not ready, but Gamelin refused. Some accounts, however, accuse Huntziger of complacency and say that General André Corap, commanding the neighbouring Ninth Army, was more aware of the threat. In any case, the concrete positions overlooking the River Meuse built by civilian contractors did not even have embrasures facing in the right direction. Minefields and barbed-wire entanglements were totally inadequate, and suggestions that trees should be felled across the forest tracks on the east bank of the river were rejected because the French cavalry might want to advance.
In the early hours of Friday, 10 May, word of the impending attack reached Brussels. Telephones began ringing all over the city. Police rushed from hotel to hotel to tell night porters to wake any military personnel they had staying there. Officers, still struggling into their uniforms, ran to find taxis to rejoin their regiments or headquarters. As dawn broke, the Luftwaffe appeared. Belgian biplane fighters took off to intercept, but their antiquated machines stood no chance. Civilians in Brussels awoke to the sound of anti-aircraft fire.
Reports of enemy movement had also reached Gamelin’s headquarters in the very early hours, but they were dismissed as an overreaction after so many false alarms. The commander-in-chief was not woken until 06.30 hours. His Grand Quartier Général in the medieval fortress of Vincennes on the eastern edge of Paris was far from the battlefield but close to the centre of power. Gamelin was a politician’s soldier, adept at maintaining his position in the byzantine world of the Third Republic. Unlike the ferociously right-wing General Maxime Weygand, whom he had replaced in 1935, the Delphic Gamelin had avoided an anti-republican reputation.
Gamelin, credited with planning the Battle of the Marne in 1914 as