To understand it more:D

To understand more the video...

The Franco-Prussian War was fought in 1870 and was provoked by Bismarck as the last step to join Germany. There were two previous wars: one in 1864 named Danish War and other one in 1866 named Austro- Prussian. Bismarck had created the North German Confederation, but still needed to convince the South German states to join. The South German states were mainly Catholic and convinced they should stay independent from Protestant North Germany.

Bismarck sent a telegram "The Ems Dispatch" from Kaiser Wilhelm to Napoleon III to make the France to declare war on Prussia in 1870. Quickly, Prussian troops overwhelmed France and Napoleon III was captured in the Battle of Sedan. The South German States Were convinced to join the new nation of Germany. This happened in January of 1871.
France had to pay a really big amount of money for losing the war. They also lost the part of territories in Alsace and Lorraine that they had at that period, and they had to watch the Germans create their new and beautiful country at Versailles outside Paris. Poor France! This was a little bit humiliating and, decades later, helped construct a huge war, a first world war.