Napoleon abdicates (conditionally) for the first time and names his son Napoleon II as Emperor of the French, followed by unconditional abdication two days later.

Napoleon Bonaparte, later known by his regnal name Napoleon I, was a French general and statesman who rose to prominence during the French Revolution and led a series of military campaigns across Europe during the French Revolutionary and Napoleonic Wars from 1796 to 1815. He led the French Republic as First Consul from 1799 to 1804, then ruled the French Empire as Emperor of the French from 1804 to 1814, and briefly again in 1815. He was King of Italy from 1805 to 1814 and Protector of the Confederation of the Rhine from 1806 to 1813.

Napoleon II was the disputed Emperor of the French for a few weeks in 1815. He was the son of Emperor Napoleon I and Empress Marie Louise, daughter of Emperor Francis I of Austria.

Emperor of the French was the title of the monarch and supreme ruler of the First French Empire and the Second French Empire. The emperor of France was an absolute monarch.

April 4 is the 94th day of the year in the Gregorian calendar; 271 days remain until the end of the year.