Napoléon François Joseph Charles Bonaparte, Duke of Reichstadt (March 20, 1811 - July 22, 1832) was the son of Napoleon Bonaparte and his second wife, Marie Louise of Austria. Known from birth as the King of Rome, he was styled as His Majesty the King of Rome, which Napoleon I declared was the courtesy title of the heir-apparent. He was briefly the second Emperor of the French.

Three years after his birth in Paris, the First French Empire - to which he was heir - collapsed, and Napoleon abdicated the throne in favour of his infant son, who was taken by the empress to Chateau de Blois in April 1814. In 1815, after his defeat at Waterloo, Napoleon again abdicated in favour of his son whom he had not seen since his exile to Elba. The Chamber of Representatives and Chamber of Peers recognized him as Emperor from the moment of his father's abdication (June 22, 1815), but the entrance of the Allies into Paris on July 7 brought a rapid end to his regime. The next Bonaparte to come to the throne of France (in 1851) took the name Napoleon III in deference to his cousin's mostly theoretical reign.

After 1815, the young prince, now known as Franz, after his maternal grandfather, rather than as Napoleon, was a virtual captive in Austria. He was awarded the title of Duke of Reichstadt in 1818. He died of tuberculosis at Schönbrunn Palace in Vienna on July 22, 1832. Upon the death of his stepfather, Neipperg, and the revelation that his mother had borne two illegitimate children to him prior to their marriage, Franz said to his friend, Prokesch von Osten, If Josephine had been my mother, my father would not have been buried at Saint Helena, and I should not be at Vienna. My mother is kind but weak; she was not the wife my father deserved.

He was very close to Princess Sophie of Bavaria and it has been further suggested that he was the father to her son, the future ill-fated Emperor Maximilian I of Mexico. Futher more it has been suggested that his death was the result of deliberate lead or arsenic poisoning at the hands of agents of Metternich's police state.

In 1940 his remains were transferred, as a gift to France from Adolf Hitler, from Vienna to the dome of Les Invalides in Paris, where he rested for some time beside his father, later being moved to the lower church. His heart and intestines remain in Vienna, in urn 42 in the Herzgruft, and his viscera are in urn 76 of the Ducal Crypt in Vienna.