After the French army has mobilized, it will inevitably deploy its elite troops in northern France. In the arrangement of these forces, the French army will inevitably focus on the eastern part of France bordering Germany, because the French army must make an all-out attack to recapture the Alsace and Lorraine iron ore areas ceded to Germany due to the failure of the Franco-Prussian War. This is a mountainous area, and the terrain is not conducive to the French attack. In this way, as long as the Germans arrange a small number of troops in Alsace and Lorraine, they can resist the attack of the French main force, while the German main force bypasses Belgium and enters the hinterland of France from the west. Because the western part of France is plain, the terrain is convenient for the German attack. The Germans should quickly defeat the French resistance in the west, open a gap in the French defense line, and then the Germans will attack eastward. The French army will attack Alsace and Lorraine according to the pre-war military plan, and temporarily changing the military plan to counter the German attack from the west is the most headache for senior French officials. A large number of deployed personnel and equipment need to be concentrated in the railway station, and then transported by train from eastern France to the west, which not only takes time but also disrupts the entire French attack on Alsace and Lorraine, and causes a great burden on railway dispatching. The siege of Paris is very important in the March. As long as the Germans quickly move closer to Paris, the French capital, and encircle and capture Paris as they did in the Franco-Prussian War decades ago, it will arouse the French people's dissatisfaction with the French wartime government and force the French wartime government to lose its prestige or even collapse because of the loss of the capital. Therefore, the French wartime government will inevitably concentrate on defending the capital. If the German army can defeat the troops hastily mobilized by the French army here, it will demoralize the French army after losing the capital. Then the German army should cross France as quickly as possible and go directly to the eastern defense line of the French army, and then attack the French army that is attacking Alsace and Lorraine, destroying all the elite troops deployed in the northern part of the French army, and France will surrender. Therefore, in the Schrieffen plan, nearly 80% of the Germans were concentrated to attack Paris by Belgium, and the plan was completed with overwhelming forces.

The existence of maginot line during World War II was not conducive to the development of German armored forces.