It’s an easy train trip from Paris and a walk through the forest (about 20 mins).
It was the private residence of Anne (a guy) de Montmorency who was the head of the army.
The chateau has a very rich history, quite apart from the collection of Renaissance furniture and objects.
The fireplaces were all painted right up to the ceilings with Biblical themes – mainly the story of Jacob (both Montmorency and king Henri II were second sons and therefore not destined to play the starring role so Jacob, who was given his older brother Esau’s birthright is obviously an obscure subject but meaningful for him).
I haven’t seen a place with all the fireplaces painted like that. It’s quite spectacular and definitely worth a visit.
Information about getting to Ecouen and the Musée National de la Renaissance can be found here.