1. The Battle of France was the largest battle since World War II broke out. The total strength of the two sides put into the battle was 7 million troops. The numbers of troops of the warring parties were roughly equal. Most of the Allied ground forces were composed by the French army. Belgium and the Netherlands had a total of 32 divisions, accounted for more than 20% of the total number of the Allies. But in fact the two countries remained neutral before the Battle of France. Their armies could not take actions in coordination with the Allies and the Allies could not enter these two countries to organize a defense. As the country’s main alliance, over eight months after the outbreak of the war, Britain had only 10 divisions in France. In addition, the Polish government in exile also organized two divisions to be involved in the Battle of France. Germany mobilized 141 divisions to be engaged in the war, which were all composed by the German army. From this comparison, it can be concluded that the Allies army were consisted of a number of countries, therefore it was significantly more difficult to command than the Germans. And directly counting the Netherlands and Belgium armies into the Allied army was not entirely reasonable because these two armies did not participate any joint actions before. Thus, although the strengths were statistically considerable, the Germans actually had some advantages. Not to mention the Battle of Poland enabled many German units to have extensive combat experience while the French army had not take part in any large-scale war since the end of World War 1.
2. Analyzed from warring potential the sum of GDP of Britain and France when the war broke out was only slightly higher than in that of Germany. The overall population of the two countries was equivalent with that of Germany. Although Britain and France both had a large number of overseas territories, except for a few British dominions, productivity and ability to mobilize of other overseas territories were very low and could only provide the supply of raw materials. Although Germany at this time suffered from the naval blockade by Britain and France, it still could get a large number of raw materials from the neutrals, and therefore would not be inferior to the opponents in the field of the military production. That is to say, Britain and France had a slight advantage in the strategy then, but the advantage was not obvious. Of course, this was directly from the belligerent perspective. To analyze in combination with the neutrals with different relations, the situation would be more complicated.
3. Before the Battle of France, there were still many big countries remaining neutral. Which camp would these countries eventually joined would lead to a significant change to the war. Two important neighbors of France, Italy and Spain had declared neutrality at that time, but both countries had maintained friendly relations with Germany, which was very unfavorable on the strategy for France. The Soviet Union located in Eastern Europe maintained a good relationship with Germany too at this time and was one of the main suppliers of raw materials of Germany. Japan kept a good relationship with Germany too. But due to remoteness, it would not have a significant impact on the situation. Among the major powerful countries, only the United States maintained a good relationship with Britain and France. By calculating the strength of these countries at the time when the war broke out, it could be seen that in terms of GDP, the sum of the four countries of Italy, Spain, the Soviet Union and Japan was approximately equal to the total GDP of the United States. As to population, these four countries had 340 million population and the United States had only 130 million. Considering the United States was a single country, while Germany’s friendly countries all had their own goals, so the degree of international support of each side could also be counted as roughly equal.
4. It was a significant blow for the Allies that Poland was annihilated. If Poland could block the joint German-Soviet offensive, the Allies would gain greater strategic advantage. But in fact this assumption did not hold, because Poland was almost impossible to resist the attack. The strength gap of the two sides was too wide.
5. On the issue of assistance to Finland, the Allies deliberately took tactics of delaying, resulting that the Allies avoided direct engagement with the Soviet Union and thus prevented the Allies from falling into the huge strategic disadvantage. In fact, no matter whether Britain and France signed a mutual defense treaty with Finland or not, they would not take substantive action. Britain and France had the treaty obligation to defend Poland before. But in the event of Soviet attack, British and French pretended not to see. To conclude, the existence ranked the first, international treaty obligations the second and international moral the third. After the Battle of France, France and the UK despite the treaty achieved a unilateral truce with Germany, which was also for the same reason.
6. The Germans developed a very successful program, which would quickly cut off the enemy’s supply lines and evacuation routes, for which the war would be ended in a short time. Casualties were also very small compared to World War 1. During World War 1, the battles in the west line lasting for several years led to over 14 million military casualties of the two sides. And during the Battle of France, the number of casualties of both sides was about 500,000 people. However, because the battle only lasted for over 40 days, indicating a very high intensity of the war. More than 10,000 people died or got injured every day.
7. The German armored forces had an outstanding performance in the battle. It fast cut off the French defense, making the Allied forces crumbled in a short time. The Luftwaffe completely overwhelmed the Allied Air Force. The majority of the French Air Force and the Royal Air Force for reinforcements was eliminated. In addition, the Luftwaffe gave strong support to ground forces.
8. Some lower-level German military generals became well known in this battle, such as Manstein developing the plan of attack, 7th Armored Division Commander Rommel, commander of the 19th Panzer Corps Guderian, et al. During World War 2, they were all raised to the rank of marshal or general.
9. After the military defeat, France quickly signed an armistice agreement with Germany to avoid suffering from greater losses. Although the move violated the agreement signed with the UK, like mentioned in the fifth point above, survival ranked the first. France through signing an agreement with Germany made their losses reduced. In fact, according to the agreement, the German occupation of northern France was only temporary. After the war with Britain ended, occupation would stop. Later, since the situation of the war changed, the Germans did not withdraw from the area. And Germany ensured to France that in the future, France could retain the overseas territories with the size that roughly equivalent to the current. So the natures of the Battle of France and the Battle of Poland were completely different. French defeat was just like the Franco-Prussian War of the 19th century or earlier Napoleonic Wars. It was just loss of interests and would entirely not jeopardize the survival of the country and territorial changes would not be too severe. But the objective of the Battle of Poland was to completely destroy a country. The Polish government naturally was unable to reach any agreement with Germany or the Soviet Union. It could only organize the government in exile to continue to fight till victory or ultimately failed.