Louis-Napoléon Bonaparte (20 April 1808 – 9 January 1873) is the first President of the French Republic and, as Napoleon III, the ruler of the Second French Empire.

He is the nephew and heir of Napoleon I.

Elected President by popular vote in 1848, he initiates a coup d'état in 1851, before ascending the throne as Napoleon III on 2 December 1852, the forty-eighth anniversary of Napoleon I's coronation.

He rules as Emperor of the French until 4 September 1870.

He is both the first titular president and the last monarch of France.

Napoleon III is primarily remembered for an energetic foreign policy which aims to jettison the limitations imposed on France since 1815 by the Concert of Europe and reassert French influence in Europe and the French colonial empire.

Napoleon stands opposed to the reactionary policies imposed at Vienna in 1815 and instead is an exponent of popular sovereignty, and a friend of nationalism A brief war against Austria in 1859 largely brings an end to the process of Italian unification.

In the Near East, Napoleon III spearheads allied action against Russia in the Crimean War and restores French presence in the Levant, claiming for France the role of protector of the Maronite Christians.

A French garrison in Rome likewise secures the Papal States against annexation by Italy, defeating the Italians at Mentana and winning the support of French Catholics for Napoleon's regime.

In the Far East, Napoleon III establishes French rule in Cochinchina and New Caledonia.

French interests in China are upheld in the Second Opium War and the Taiping Rebellion; an abortive campaign against Korea is launched in 1866 while a military mission to Japan fails to prevent the restoration of Imperial rule.

French intervention in Mexico is also unsuccessful and is terminated in 1867 due to mounting Mexican resistance and American diplomatic pressure.

Domestically, Napoleon is balanced between the conservatives and liberals, and year by year moves bit by bit toward the liberal element.

It is an era of prosperity and industrialization urban France.

This facilitates a major renovation of Paris under Haussmann that creates the outline of the modern city.

The Second French Empire is overthrown three days after Napoleon's disastrous surrender at the Battle of Sedan in 1870, which results in the proclamation of the French Third Republic and his exile in England.