Excerpts from Books and Wikipedia
"The Battle of Sedan was fought during the Franco–Prussian War from 1 to 2 September 1870. It resulted in the capture of Emperor Napoleon III and large numbers of his troops and for all intents and purposes decided the war in favour of Prussia and its allies, though fighting continued under a new French government. . . . The Meuse Army and the Prussian Third Army, commanded by Field-Marshal Helmuth von Moltke and accompanied by Prussian King Wilhelm I and Prussian Chancellor Otto von Bismarck, cornered MacMahon's army at Sedan in a massive encirclement battle." [Wikipedia] "Prussian victory spelled doom for the French army in the Franco-Prussian War, leading to consolidation of Germanic states into one country, as well as long-standing hostility between France and Germany to serve as one causal factor in the outbreak of World War I. . . . France's defeat ended Napoleon's Second Empire, ushering in the Second Republic. . . . Allying itself with Great Britain, which feared the increasing size of the Germany, France rebuilt itself into a colonial power, a strategy that aided in restoring the nation's morale at the end of the century."