The First French Empire (Empire Français), also known as the Greater French Empire or Napoleonic Empire, was the empire of Napoleon I of France. It was the dominant power of much of continental Europe at the beginning of the 19th century.

Napoleon became Emperor of the French (L'Empereur des Français, lɑ̃.pʁœʁ dɛ fʁɑ̃.sɛpron) on 18 May 1804 and crowned Emperor on 2 December 1804, ending the period of the French Consulate, and won early military victories in the War of the Third Coalition against Austria, Prussia, Russia, Portugal, and allied nations, notably at the Battle of Austerlitz (1805) and the Battle of Friedland (1807). The Treaty of Tilsit in July 1807 ended two years of bloodshed on the European continent.

The subsequent series of wars known collectively as the Napoleonic Wars extended French influence over much of Western Europe and into Poland. At its height in 1812, the French Empire had 130 départements, ruled over 44 million subjects, maintained an extensive military presence in Germany, Italy, Spain, and the Duchy of Warsaw, and could count Prussia and Austria as nominal allies. Early French victories exported many ideological features of the French Revolution throughout Europe. Seigneurial dues and seigneurial justice were abolished, aristocratic privileges were eliminated in all places except Poland, and the introduction of the Napoleonic Code throughout the continent increased legal equality, established jury systems, and legalized divorce. However Napoleon also placed relatives on the thrones of several European countries and granted many noble titles, most of which were not recognized after the empire fell.

Historians have estimated the death toll from the Napoleonic Wars to be 6.5 million people, or 15% of the French Empire's subjects. In particular, French losses in the Peninsular War in Spain severely weakened the Empire; after victory over the Austrian Empire in the War of the Fifth Coalition (1809) Napoleon deployed over 600,000 troops to attack Russia in the catastrophic French invasion of the Russian Empire in 1812. The War of the Sixth Coalition saw the expulsion of French forces from Germany in 1813.

Napoleon abdicated in 11 April 1814. The Empire was briefly restored during the Hundred Days period in 1815 until Napoleon's defeat at the Battle of Waterloo. It was followed by the restored monarchy of the House of Bourbon.