Short answers, pulled from the story.
The 1814 campaign in north-east France was Napoleon's final campaign of the War of the Sixth Coalition. Following their victory at Leipzig in 1813, Austrian, Prussian, Russian, and other German armies invaded France. Despite Napoleon inflicting several defeats, including the Six Days' Campaign, the Coalition eventually captured Paris and forced Napoleon's abdication.
The Six Days' Campaign refers to a sequence of four victories Napoleon won between the 10th and the 14th of February 1814 against the Army of Silesia under Blücher. He defeated Russian and Prussian forces at Champaubert, Montmirail, Chateau-Thierry, and Vauchamps in rapid succession, forcing the entire Army of Silesia into retreat.
Napoleon won numerous engagements but faced an overwhelming numerical disadvantage, with fewer than 80,000 troops available on the eastern frontier against Coalition forces numbering in the hundreds of thousands. A letter he wrote to Empress Marie-Louise outlining his strategy was intercepted by Cossacks on the 22nd of March 1814, exposing his plans and prompting the Coalition to march directly on Paris.
The marie-louises were very young and inexperienced conscripts called up by a senatus consultum of the 9th of October 1813, drawn from the conscript classes of 1814 and 1815. They were nicknamed after the young Empress Marie-Louise and formed the bulk of Napoleon's new French Army during the 1814 campaign.
Marshals Marmont and Mortier positioned their troops on the heights of Montmartre to defend Paris, but on the 31st of March 1814 the French commanders judged further resistance hopeless and surrendered the city. Napoleon's marshals subsequently refused his order to march on Paris, unanimously overruling him to spare the city from destruction.
Napoleon first abdicated in favour of his son on the 4th of April 1814, with Marie-Louise as regent, but the Coalition refused this arrangement. Two days later he signed the Treaty of Fontainebleau, announcing his unconditional abdication. He was exiled to the island of Elba, the French monarchy under Louis XVIII was restored, and the Treaty of Paris of the 30th of May 1814 returned France to its 1792 borders.