Napoleon II was the disputed Emperor of the French for a few weeks in 1815. He was the son of Emperor Napoleon I and Empress Marie Louise, daughter of Emperor Francis I of Austria. Napoleon II had been Prince Imperial of France and King of Rome since birth. After the fall of his father, he lived the rest of his life in Vienna and was known in the Austrian court as Franz, Duke of Reichstadt for his adult life. He was posthumously given the nickname L'Aiglon after the popular Edmond Rostand play, L'Aiglon.

Emperor of the French was the title of the monarch and supreme ruler of the First and the Second French Empires.