Fifteenth century bedroom at Burg Eltz castle, Germany.
I adore the bed. Bed curtains served multiple purposes. They allowed privacy — consider that many people, even rich people, shared their bedrooms with other people, such as guests or servants. Medieval structures often lacked hallways as we think of them; one went through one room to get to the next. So people (guests, servants, children, etc) might walk through one’s bedroom to get somewhere else. And bed curtains helped (in theory) to keep vermin away.
Notice, too, how sparse the room is — there’s a bed, some benches, a table. Now, we can’t see the whole room in this picture, but there’s probably not much else. A fireplace, perhaps, a wardrobe.
Painted walls were very common in the late Gothic period; the paint mimics expensive tapestries. I was lucky enough to visit a small castle like this when I was in German (Burg Trausnitz in Landshut) and it also featured painted walls.