Napoleon had about 200,000 men in all, of whom upwards of 100,000 were held by the Duke of Wellington on the Spanish frontier (see Invasion of south-west France), and 20,000 more were required to watch the debouches from the Alps.

Having learnt that Napoleon was at hand Blücher fell back a few miles to the east the next morning to a strong position covering the exits from the Bar-sur-Aube defile.

The weather was terrible, and the ground so heavy that the French guns, the mainstay of Napoleon's whole system of warfare, were useless and in the drifts of snow which at intervals swept across the field, the columns lost their direction and many were severely handled by the Cossacks.

But on 4 February Blücher, chafing at this inaction, obtained the permission of his own sovereign, King Frederick III Prussia, to transfer his line of operations to the valley of the Marne; Pahlen's corps of Cossacks were assigned to him to cover his left and maintain communication with the Austrians.

[2] Believing himself secure behind this screen, Blücher advanced from Vitry along the roads leading down the valley of the Marne, with his columns widely separated for convenience of subsistence and shelter the latter being almost essential in the terrible weather prevailing.

Blücher himself on the night of 7/8 February was at Sézanne, on the exposed flank so as to be nearer to his sources of intelligence, and the rest of his army were distributed in four small corps at or near Épernay, Montmirail and Étoges; reinforcements also were on their way to join him and were then about Vitry.

[4] Napoleon then turned on the main body of the Army of Silesia and on 14 February defeated Blücher in the Battle of Vauchamps near Étoges, pursuing the latter towards Vertus.

[4][11] These disasters compelled the retreat of the whole Silesian army, and Napoleon, leaving detachments with Marshals Mortier and Marmont to deal with them, hurried back to Troyes.

To add to Allied woes, French partisan warfare was beginning to take shape...[12] David Zabecki wrote in Germany at War (2014): Later commentators noted that in this campaign Napoleon achieved unexpected and extraordinary results, including the elimination of approximately 20,000 enemy troops, which nearly halved the forces he then faced.

Napoleon's troops had been greatly outnumbered, and he therefore fought by means of careful tactical manoeuvring, rather than using the sort of brute force characteristic of earlier French victories.

The Coalition commanders held a council of war at Pougy on the 23 March and initially decided to follow Napoleon, but the next day Tsar Alexander I of Russia and King Frederick of Prussia along with their advisers reconsidered, and realising the weakness of their opponent, decided to march to Paris (then an open city), and let Napoleon do his worst to their lines of communications.

The Battle of Paris ended when the French commanders, seeing further resistance to be hopeless, surrendered the city on 31 March, just as Napoleon, with the wreck of the Guards and a mere handful of other detachments, was hurrying across the rear of the Austrians towards Fontainebleau to join them.