The Grande Armée had been battered so badly at Eylau, Andrew Roberts explains (in Napoleon: A Life), that it could not follow up the victory, as it had after Jena:
Soult’s aide-de-camp Colonel Alfred de Saint-Chamans recalled after the battle, ‘The Emperor was passing in front of the troops; in the middle of cries of “Vive l’Empereur!” I heard many soldiers cry “Vive la paix!”, others “Vive la paix et la France!”, others even shouted “Pain et paix!” [Bread and peace!]’ It was the first time he had seen the morale of the army ‘a bit shaken’, which he put down to ‘the butchery of Eylau’.
The day after the battle, Napoleon announced in a bulletin that an eagle had been lost, and said, ‘The Emperor will give that battalion another standard after it has taken one from the enemy.’ The reason the unit wasn’t named was that in fact five eagles had been lost.