Intelligence in History: The Fall of France

In 1940, the German invasion of France through the Ardennes was a last-minute decision, due in part to the Maginot Line and the fact that Allied intelligence had obtained an early draft of Fall Gelb, which detailed German plans for an attack on France. As a result, the Germans had to change their plan very fast.

Several flaws in the processes and attitudes of French Intelligence manifested in poor military communications, which severely hindered Allied attempts to adequately prepare for attack. In theory, the French Intelligence unit was quite impressive, as it was able to glean information ahead of time on the invasions of the Rhineland, Poland, and the annexation of Czechoslovakia. Unfortunately, although the Allied forces were forewarned of the incoming German forces, they were not prepared.

If they had the information, what prevented acting upon it?

The flaw that begat all others laid in how the Deuxieme Bureau of General Staff handled the intelligence that it was supplied to them. The Deuxieme would compare the information acquired from the Service de Renseignements (SR), which collected strictly military information as opposed to that of the French Ministry of Foreign Affairs. As such, they had to draw their own conclusions from the separate sources. Since the intelligence reached Gamelin from a variety of sources, it was bound to lead to confusion – especially when considering the strained relationship between the SR and the French Ministry of Foreign Affairs.

Inexperience in the field was another issue of concern, as assignment to intelligence did not require very intense qualifications, nor was it a prioritized job. Often, qualified intelligence agents were overlooked in favor of the opinions of students from the Ecole Superieure de la Guerre – a prestigious military school – who were regarded as something of an intellectual elite. This was not the only instance of voices going unheard, as – according to Historian Douglas Porch, the French Army was one that had a rigid definition of what was the ‘right’ way of doing things, and what was different, or ‘wrong.’ (Porch, p. 29)

These forces bred an issue with complacency, since voices against the grain were frequently shut down by military attaches’ that conformed to the opinions of their superiors. It seemed that ‘observe and report’ was the way to function in the French Intelligence services as opposed to freely discussing differing perspectives and suggestions. The situation worsened to the point that the SR would exaggerate German numbers in an attempt to garner the attention and serious regard of their superiors; later studies on this subject illustrated that French estimates of German forces were as much as twenty percent higher than British figures. Basically, the French Intelligence operated in an environment that was hostile to it – on their own side.

Furthermore, the difficulties of the compartmentalized structure of the Allied forces, tumultuous political landscape, and poor decisions of the French High Command combined to pave the way to success for the German operations Fall Gelb and Fall Rot. The procedures that the French had for making decisions and carrying them out was incredibly cumbersome – it seemed that France, like other democracies, was better prepared for handling internal issues than mobilizing its citizens against a foreign invader. French Intelligence was not the only system that operated in ill-fitted surroundings, indeed the thought could have been generalized to the military body as a whole. Its officers were by and large conservative, or even monarchist, which resulted in a lot of political constraints – the primary consequence of which was that their voices were often dismissed. Compartmentalization also was a rampant issue in the armed forces, where commanders and operations officers formed an elite that were kept separate from staff that dealt with intelligence and supply. Together with the strained relations between the Ministry of Foreign Affairs and the SR, the flow of communication was severely hindered, as historians Douglas Porch and Ernest May both attribute the recipe for defeat to these phenomenons.

The Effect of Hubris

Arrogance among the high command was yet another issue that clouded the good judgment of Allied forces. Recall that the opinion was that tactical decisions ought to have been left to the “intellectually superior” men of the Ecole Supérieure de la Guerre. This thought in itself immediately diminished the value of opinions from other men. Gamelin himself admitted to having considered the notion of an invasion through the Ardennes, but dismissed the thought on the basis of the forest being a poor corridor to move an army. What Gamelin did not consider was that the Germans were willing to weather the inconvenience. In 1939, the French army was prepared for a long-term war – rather, a war that followed their own notions of tactics. They planned to hold a defensive front for two years, which would be succeeded by the mobilization of economy and joint allied resources. The result was that the center of the whole front was left lightly defended, on the basis of the assumption that the Ardennes and River Meuse would be a poor avenue of attack. As we see now, looking back on the Fall of France in 1940, that was very much not the case for what happened.

Overall, the Battle of France in 1940 ought to have been a victory on the behalf of the Allies, but was lost due to failings in communications, the political environment, judgment of enemy movements, and poor tactical decisions. Specifically, German equipment was actually inferior to French equipment and numbers, and their final plan Fall Gelb was actually a hastily conjured idea after the French had acquired the earlier drafts of it. In France, however, there were several issues with complacency and conformity in terms of decisions to be made for the military, and often the suspicions of intelligence agents went unheard, and that escalated further into the military command having tight political constraints with the French government. Even the French government was unstable, with widespread fracturing among political divisions, which contributed to a hostile atmosphere for the Allied army to function in. Blind confidence in their own decisions clouded the view of the French High Command, who left the Ardennes only lightly defended after concluding that it would be unlikely to be attacked. Thus, the German army was able to establish a foothold and push through to successfully invade France.


May, Ernest. Strange Victory: Hitler’s Conquest of France. Hill and Wang: New York, October 3, 2001.

Porch, Douglas. “French Intelligence and the Fall of France, 1930-40”. Intelligence and National Security: Vol. 4, Issue 1. 1989, pp. 28-58

This article was written by Kristina Weber, Content Supervisor of Centry. She holds a Bachelor’s Degree in History from the University of Calgary.

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