Napoléon-Joseph-Charles-Paul Bonaparte (born Sept. 9, 1822, Trieste—died March 17, 1891, Rome) was the youngest son of Jérôme Bonaparte, Napoleon I’s youngest brother, and his second wife, Catherine of Württemberg. In 1852 he was named heir presumptive to the throne of the Second Empire.
After the French Revolution of 1848, he was elected to the National Assembly as a representative of Corsica and assumed the name of Jérôme. Notwithstanding his ostensible opposition to the coup d’etat of 1851 on the establishment of the empire, he was designated successor to the throne, as Prince Napoléon-Jérôme, if Napoleon III should die childless. Associating mainly with men of progressive ideas, he represented at court liberal opinion against the empress Eugénie.
In 1854 he took part in the Crimean campaign as general of a division. (About this time he became known as “Plon Plon,” supposedly because soldiers who fought under his command thought him a coward and nicknamed him “Plomb-plomb” or “Craint-plomb,” meaning “Fear-lead.”) Returning to France, he undertook the direction of the national exhibition for the international exhibition of 1855. In 1858 he was appointed minister for the colonies and Algeria. He found his political activity was diverted into a different channel by his sudden marriage in 1859 to the princess Maria Clotilde of Savoy, daughter of Victor Emmanuel II, the king of Sardinia. When the war for the liberation of Italy broke out, Prince Napoléon-Jérôme commanded the French corps that occupied Tuscany.
In the last years of the Second Empire Prince Napoléon-Jérôme lost all his official dignities as the result of several indiscreet speeches. After the fall of the empire he lived in comparative retirement until, in 1879, the death of Napoleon III’s son made him direct heir to the Napoleonic succession. As the Bonapartist pretender he was unfortunate and inglorious, and before his death he was virtually deposed in favour of his elder son, Napoléon-Victor-Jérôme (1862–1926). The latter became the recognized Bonapartist pretender on his father’s death in 1891.