FRANCO-GERMAN WAR
1870 - 1871

This war between France and Germany was fought from July 19, 1870 until May 10, 1871. It is also called the Franco-Prussian War, as Prussia was leading several German states in the fight.

War was desired by both countries:

French Emperor Napoleon III, not very admired by his people, thought the war would boost his popularity.

Prussian chancellor Otto von Bismarck was sick and tired of Germany's many small states. He was ready to unite all of them - under Prussian leadership, of course.

Hot topic of the day
Germany was ready to put one of their princes (Prince Leopold of Hohenzollern-Sigmaringen) on the Spanish throne, which Queen Isabella II of Spain had left vacant. France felt potentially squeezed between the two countries (see any map) and sent an ambassador to the Prussian king.

Sneaky Bismarck published his edited version of the conversation with the ambassador to provoke the French to declare war. It worked like a charm. French Emperor Napoleon III indeed declared war on Germany. Because France was now officially the aggressor, all German states (except Austria) chimed in and eventually formed what is your Germany today. 

On the French side, Napoleon III completely lost all his power and influence. France had to surrender, the French monarchy was abolished, and the French Third Republic was proclaimed. Napoleon was released by the Germans and went to England, where he died in 1873 whilst cursing his bladder stones.

WINNER
Notable happy German faces of the day were king William I of Prussia (proclaimed Kaiser Wilhelm of Germany after this war,) Prussian chancellor and mastermind Otto von Bismarck and General Helmuth von Moltke.

WERE ANY FAMOUS PEOPLE INVOLVED IN THIS WAR?
German thinker Friedrich Nietzsche helped the wounded of this war, who returned the favor and gave him diphtheria.

And here is the map:

Franco-Prussian War 1870-1871
Click map to enlarge