Your challenge, should you choose to accept it, is to have the Second French Empire, ruled by Emperor Napoleon III, to defeat Prussia in the Franco-Prussian War with a POD no earlier than 1862. Can it be done? How? What would be the aftereffects?
IOTL, France had a superior navy to Prussia at this time, but was bogged down in a Transatlantic conflict in Mexico. On the other hand, Prussia had recently defeated its rival for German unification, Austria, and had established its role as the dominant member of the North German Confederation. Chancellor Otto van Bismarck believed that Prussia needed to win a war against a powerful opponent, such as France, to facilitate German unification. Had Prussia been defeated instead, would German unification be delayed? And would France take its own "Alsace-Lorraine" as compensation?