With permission from your landlord the easiest would be to prime with something like kitlz then paint.

Thanks

Not sure what you mean by “mixed wallpaper and plaster”. Wallpaper is applied to plaster (or wallboard) as a decorative finish.

From your photo it looks like what you have is wallpaper pealing off plaster. Which should be a landlord repair issue. My experience has been that wallpaper comes off plaster relatively easily. YMMV significantly.

No telling what the condition of the plaster is under the wallpaper.

Personally, I think painting wallpaper is a terrible idea. It makes removal later difficult. Generally the issues with the wall and wallpaper conditions are not corrected and show. And what ever texture there is in the wallpaper will show through, including seam locations.

In conclusion, the best thing to do is remove the wallpaper, correct all wall issues, and paint or rewallpaper. As a tenant the final solution may not be yours. This type of work should always be discussed with your landlord and the decision put in writing and signed by both parties.

I would not paint over wallpaper either. That is terrible to remove in the future, and the wallpaper in your picture is already peeling in places. You landlord would probably not be very happy if you painted it, and made the wallpaper removal a bigger job than it should be. If he says, you can remove it, then, I would remove it. Once it is removed, you will be able to see the condition of the plaster. You may end up having to wallpaper it again, in a nicer color that is more appealing to you, and is clean and fresh. Besides, painting over that wallpaper, wouldnt look good. It is loose in places, and peeled completely off in at least one place.

If you paint over the wallpaper, the paint may loosen the paper further, and you will end up with a wet, gooey mess on the floor.

Why isn't the landlord doing this?