The battle of La-Fere-Champenoise (25 March 1814) was a French defeat that signalled the failure of Napoleon's last gamble during the campaign of 1814 and saw Schwarzenberg defeat Marmont and Mortier on the road to Paris.
Earlier in the campaign Napoleon had managed to win a series of battles that kept his enemies off balance. Blucher's first attempt to reach Paris had been ended by the Six Days Campaign (Champaubert (10 February), Montmirail (11 February), Chateau-Thierry (12 February) and Vauchamps (14 February) ), while Schwarzenberg's advance down the Seine was stopped at Mormant (17 February 1814), Valjouen (17 February 1814) and Montereau (18 February 1814). This was the high point of Napoleon's military success during the campaign, and after this his blows failed to connect. An attempt to defeat Schwarzenberg on the Aube failed because the Austrian commander was always willing to retreat out of danger. At the same time Blucher made another move on Paris, forcing Napoleon to move back to deal with him once again. Blucher was forced to retreat north of the Aisne, but after a narrow French victory at Craonne (7 March 1814) the French suffered a serious defeat at Laon (9-10 March 1814), where Marmont's command suffered heavy losses and only Blucher's illness on the second day of the campaign saved the French from a more serious defeat. Napoleon retreated back to the Aisne, before winning his last significant victory of the campaign, at Rheims (13 March 1814). This caused a panic in the Allied command, but unlike after earlier setbacks didn't produce a new peace offer.
Napoleon now made what proved to be a fatal mistake. He decided to move east onto the Marne, to link up with the troops currently trapped in the border fortresses (in particular Metz and Verdun), and try and threaten the Allied lines of communication. His expectation was this would force Blucher and Schwarzenberg to retreat in order to deal with this threat. The plan badly backfired. An attack on what Napoleon believed was Schwarzenberg's rearguard at Arcis-sur-Aube (20-21 March 1814) nearly ended in disaster when the French ran into most of Schwarzenberg's army, but they were saved by Schwarzenberg's reluctance to attack on the second day of the battle.
On 22 March Napoleon moved to Ormes, north-west of Arcis. He then decided to continue with his plan, and moved east to St. Dizier on the upper Marne (arriving on 23 March). Unfortunately for the French the Allies captured a letter from Napoleon to the Empress explaining his plans, and decided to gamble. Their first plan was for Schwarzenberg to move north to join Blucher, establish new lines of communications via Holland and them resume the offensive, acting against Napoleon's rear areas. They then captured messages that revealed Paris was in a state of panic, and on 24 March Tsar Alexander decided to head straight for Paris. Winzingerode with a force of cavalry and light infantry was to move to St. Dizier to trick Napoleon, while the main Allied armies combined and advanced down the Marne towards Paris.
By the end of 24 March Marmont and Mortier were in serious trouble. They now occupied a narrow strip between the Aube and the Marne, with Blucher to their north and Schwarzenberg to their east and south. However they didn't yet realise how much trouble they were in, and were still obeying earlier orders to join Napoleon.
Early on 25 March the main Allied column began to advance west along the main road from Vitry towards La-Fere-Champenoise. At this point Marmont's forces were in camp at Soude-Saint-Croix, east of Sommesous, on the main road. This put him directly in the way of the Allied advance. Mortier was about five miles to the north-west, advancing up the Soude valley from Vatry.
Marmont's men were still in their camps when the first Allied cavalry appeared on the opposite side of the Soude. He was forced to deploy while being watched by an ever increasing force of Allied cavalry, and was soon under attack. Marmont realised that he wasn't strong enough to defend Soude-Saint-Croix until Mortier arrived, and so began a retreat west down the main road.
In the north Mortier's leading troops ran into the Allies at Dommartin, not too far to the north of Soude-Saint-Croix. He was unable to make any more progress south, and like Marmont was forced to retreat west. The two Marshals united their corps around Sommesous, a third of the way back towards La-Fere-Champenoise. As more Allied troops arrived, Marmont and Mortier decided to pull back once again, this time to Connantrey, just to the east of La-Fere-Champenoise.
This retreat didn't go smoothly. First the French were hindered by a sudden hail storm, and then they ran into an awkward ravine near Connantrey, and their line was badly disordered. The Allied cavalry took advantage of this to attack, and both marshals were briefly swept up in the chaos. They were then forced to take shelter in French infantry squares until the line could be restored around the village. This was only a temporary reprieve, and under heavy pressure the French line broke and couldn't be restored until they reached the Linthes heights, west of La-Fere-Champenoise. The Allies soon broke this line as well, and the French were forced back to Allemant, north-west of Linthes.
The French were now saved by a lucky coincidence. To the north of the main battlefield a National Guard unit under General Pacthod which had been moving west from Vatry at the start of the day, escorting a food convoy. At about 10am he was ordered to halt in Villesneux, to the north of the fighting. He was then attacked by Russian cavalry, and had to try and retreat in squares towards La-Fere-Champenoise. By the time he arrived outside that town it had fallen to the Allies, but his approach forced them to recall the troops pursuing Marmont and Mortier. While the Marshals made their escape, Pacthod's force was overwhelmed and the few survivors were forced to surrender. Generals Pacthod and Amey were amongst the prisoners.
In the course of the day Marmont and Mortier had lost 10,000 men and at least 60 guns, just over half of their entire army. The Allies lost 4,000 men, a sign of the fierce fighting during the day, but with Marmont and Mortier out of the way Schwarzenberg and Blucher were able to unite their armies, and there were soon 180,000 Allied troops heading for Paris.
On 27 March news reached Napoleon of the defeat at La Fere Champenoise. Although he had fought battles nearer to Paris earlier in the campaign, the Emperor was now too far from his capital to take part in its defense. While he rushed west at top speed, the Allies closed in on Paris. Marmont and Mortier managed to scrape together a defensive force than help up the Allies at Montmartre (30 March 1814), but it was clear that the city couldn't be held. That night they negotiated surrender terms, and on the morning of 31 March the French garrison marched out and the Allies marched in. Napoleon attempted to gather one more army at Fontainbleau, south of Paris, but he finally lost the support of his marshals, and was forced to abdicate for the first time.