Query: What was the effect of that new group on the European balance of power?
Context: In the aftermath of the Austro–Prussian War of 1866, Prussia had annexed numerous territories and formed the North German Confederation. This new power destabilized the European balance of power established by the Congress of Vienna in 1815 after the Napoleonic Wars. Napoleon III, then the emperor of France, demanded compensations in Belgium and on the left bank of the Rhine to secure France's strategic position, which the Prussian chancellor, Otto von Bismarck, flatly refused.