Napoleon III captured at the Battle of Sedan Dialogue with Prussian Prime Minister Otto von Bismarck

Louis Bonaparte (Napoleon's nephew, Napoleon III) established the Second Empire of France. After becoming Emperor of France, he implemented feudal autocracy at home and launched an expansionist war abroad. He wanted to dominate Europe, so that various contradictions in the country intensified. In order to get rid of the domestic political crisis and save the crumbling imperial rule, Louis Bonaparte decided to fight against Prussia. Therefore, he used the issue of succession to the Spanish throne as an excuse to declare war on Prussia on July 19, 1870.

At the beginning of the war, it was defensive for Prussia. However, Prussian Prime Minister Bismarck also had ambitions to invade French territory. In order to enable the broad masses of the people to correctly treat the war, the General Committee of the First International drafted the first declaration on the Franco-Prussian War by Marx on July 23. The "Manifesto" analyzed the nature of war and called on the French working class to resolutely oppose the dynastic war launched by Louis Bonaparte. At the same time, it pointed out to German workers that the interests of the entire German people should not be confused with the interests of the Prussian Dynasty, and must not "allow the current war to lose its purely defensive nature and become a war against the French people." Marx also pointed out in the Manifesto: "Regardless of the outcome of Louis Bonaparte's war with Prussia, the death knell of the Second Reich has already sounded in Paris."

At the beginning of the war, the corruption of the French army was fully exposed. The equipment is not complete, there is a shortage of food and fodder, insufficient ammunition, and even the officers cannot find their own company. On August 2, the French army broke into the German territory and was hit head-on by the Prussian army. On August 6, the entire French army collapsed. The main French force was divided into two parts: one part led by Marshal Bazin was surrounded by Prussian troops at Fort Metz; the other part led by Marshal McMahon fled to Sedan in confusion. Louis Bonaparte, who served as commander-in-chief of the former enemy, also fled here with the army. The Prussian army followed and pursued and surrounded Sedang. At dawn on September 1, 1870, the French and French armies fought in Sedan. Under the fierce artillery bombardment of the Prussian army, France lost its helmets and armor and was completely defeated. It raised the white flag that afternoon and submitted its surrender. The next day, Louis Bonaparte, along with the Marshal, 39 generals, and 104,000 soldiers, was taken prisoner by the Prussian army.