You aren't damaging the property or anything like that if your only offence is leaving your curtains open at night. As long as you're paying your rent on time, she can't kick you out for that. Read your contract. If, for some stupid reason, it says you have to close the curtains at night or something like that, comply. Otherwise, your landlady needs to get over herself. I hate landlords/ladies who just do whatever they want to the tenants, regardless of the law.

That's extreme...now on the first floor I could understand...I would usually go to the roof to look at the stars or to an open field...try that next time

Can you say "Paranoid"

Buy a tension rod, hang a curtain from it. set the rod in the middle of the window so that when you look up you can see the stars, but the lower half has curtains closed.

U can't get kicked out for that shit. Tell the bitch to take u to court.

Just like loads of others said, check the contract! If it doesn't mention anything about the curtains, next time she confronts you politely remind her that you're completely entitled to keep them open. If not, get curtains that don't match the rest of the complex and hang THEM up instead!

Hold on now. First, I want to know if anyone can actually see anything into op's room. Maybe the landlord has been receiving complaints. 3rd floor up is not the same as 20th floor. People still might be able to see things if op is a nudist or has a disco light collection or something.