Jean-Christophe is the great-great-great-grand-nephew of Emperor Napoleon I (who has no legitimate direct descendants) through the emperor's youngest brother, Jérôme, King of Westphalia. Through his mother, he is a descendant of King Louis XIV of France and through his great-grandmother, Princess Clémentine of Belgium, he descends from Leopold II of Belgium, William IV, Prince of Orange, Charles III of Spain, Frederick William I of Prussia, George II of Great Britain and Louis Philippe I, King of the French, who was the last king to rule France, while his great-great-grandfather was Prince Napoléon Bonaparte, the cousin of the Emperor Napoleon III, France's most recent monarch.