Franco-Prussian War, 1870–71, a war between France and Germany. The opponents of France at the start of the war were an alliance of several confederated and independent German states led by Prussia. The Germans won the war quickly and overwhelmingly. As the Germans neared victory during the last days of the war, the various German states united under Prussian leadership to form a German nation. In France Emperor Napoleon III was overthrown and the Third Republic established. The Franco-Prussian War caused a great shift of political influence and permanently altered the balance of power in Europe.