On March 30 to 31, 1814, the battle for Paris was fought. Napoleon was advancing to Paris to reinforce his troops, but with Russian in control of the Montmartre Heights and Prussian troops ready to take the fight into the streets of Paris, Marshall Marmont contacted the Coalition and reached a secret agreement with them to spare Paris.
On March 31, Prince Talleyrand gave the key of the city to Tsar Alexander The Tsar and his staff entered the city followed by the King of Prussia and Prince Schwarzenberg. The city had feared for its safety. However, Tsar Alexander made it clear that he regarded Napoleon as the enemy of Europe—not France. He entered the city as a liberator, riding a white horse, and was cheered as the man who has spared Paris looting, burning, and destruction.
On April 2, the French Senate passed an act to declare Napoleon deposed. Napoleon had advanced as far as Fontainebleau and heard that Paris had surrendered. His marshals would not fight with him and urged surrender. On April 4, Napoleon abdicated in favor of his son, the King of Rome, but this was not to be allowed. Napoleon had to abdicate unconditionally, and he did so on April 6, and was exiled to Elba. On April 11, the war was officially over when the Treaty of Fontainebleau was signed—Napoleon took a poison that had been mixed for him and that he carried with him in case of capture. But the mix of belladonna and opium had lost its potency, and doctors revived him. He recovered and left for Elba on April 20. However, it is thought that he never regained full heath for stomach problems plagued him the rest of his life.