Prince Karl Phillip zu Schwarzenberg’s Army of Bohemia defeated Napoleon’s army at Arcis-sur-Aube on 20-21 March 1814, but did not immediately pursue the retreating enemy. Napoleon reached St Dizier on 23 March.
On 22 March a patrol of Cossacks from Prince Gebhardt von Blücher’s Army of Silesia captured a French courier who was carrying a letter from Napoleon to his Empress, Marie-Louise. It revealed that the Emperor planned to attack Schwarzenberg’s communications in order to draw the enemy away from Paris.
Blücher sent a copy of the captured letter to the main Coalition headquarters with the Army of Bohemia. A conference between Schwarzenberg, Tsar Alexander, King Friedrich Wilhelm of Prussia and their staffs on 23 March decided that the two Coalition armies should unite and pursue Napoleon.
The Coalition commanders then received further captured dispatches. They showed that the morale of the French army and it commanders was low, and that the Paris police chief feared that its population might not stay loyal to Napoleon if the enemy approached the capital. These convinced Alexander that the Coalition armies should advance on Paris.
On 24 March the Tsar persuaded Friedrich Wilhelm and Schwarzenberg that this was the right thing to do. Moving to a rich region that it yet to see fighting would make it far easier to supply the Coalition armies than would be the case if they followed Napoleon through an area that had already been ravaged by war. Paris was far more important politically to Napoleon than Berlin, Vienna or Moscow were to his enemies.
General Ferdinand von Winzengerode was ordered to pursue Napoleon with 8,000 cavalry. He was to trick the Emperor into thinking that both Coalition armies were following him, and to make sure that the Coalition command knew where Napoleon was. The rest of the Coalition armies were to advance on Paris
The Coalition cavalry advance guard under General Pyotr Pahlen and the Crown Prince of Württemberg encountered the corps of Marshal Auguste de Marmont and Édouard Mortier at La Fère Champenoise at about 8 am on 25 March. Initially 5,700 Coalition cavalry and 36 guns, later reinforced by 2,500 more Austrian cavalry, faced 12,300 French infantry, 4.350 cavalry and 68 guns.
The French cavalry were driven off the field and two light infantry regiments were forced to surrender. Marmont and Mortier could see that there were large numbers of enemy troops advancing on them, so retreated the rest of their troops in good order until about 2 pm. The Russian heavy cavalry of General Nikolai Preradovich’s 1st Cuirassier Division then arrived, bringing the Coalition force up to 12,000 men, and a heavy rain and hail storm started.
With rain and hail blowing into their faces, the French infantry were unable to fire their muskets. Two squares gave way under fire from Russian horse artillery, and many of the French infantry panicked and ran.
At the same time the sounds of another battle behind the Coalition cavalry could be heard. Neither side knew what this meant. Was it Napoleon marching to the rescue of Marmont and Mortier? In fat two French National Guard divisions, escorting a large convoy of guns and supply wagons, were being attacked by two cavalry divisions from the Army of Silesia.
The 5,000 inexperienced French troops, commanded by Generals Michel-Marie Pacthod and François-Pierre-Joseph Amey, fought gallantly against Baron Korff and General Ilarion Vasilchikov’s 4,000 cavalry and three horse artillery batteries. They had to abandon their supply wagons as they retreated in square. Eventually their retreat brought them into contact with the main Coalition cavalry force. Most of the Frenchmen were killed or forced to surrender.
The National Guardsmen fought very bravely, but the French suffered very heavy losses at La Fère Champenoise. Dominic Lieven estimates that they lost half of 23,000 men and almost all their guns in a fight with 16,000 Coalition cavalry. F. Loraine Petre says that the French lost over 10,000 men killed, wounded and captured and 60 guns against 2,000 Coalition casualties.
 Unless otherwise stated troop strengths are from D. C. B. Lieven, Russia against Napoleon: The Battle for Europe, 1807 to 1814 (London: Penguin, 2010), pp. 509-11.
 Ibid., p. 511.
 F. L. Petre, Napoleon at Bay 1814 (London: John Lane, The Bodley Head, 1914), p. 192.