one option is to use plexiglass panels - drill tiny holes in the corners and attach them with wire to the railing

Thanks. can you please provide an image of that?

Thanks. my concern is that the plexiglass will get dirty and will be hard to clean guven it will be up against the existing fence

anything transparent for the view will need to be cleaned - maybe you could find a fine gauged mesh wire fencing

Before you do anything, check with your HOA or building management to see if they'll allow you to add anything to the terrace. If so, something like this could work:

Patio - The Catio - Smith House · More Info

Comfy Catio (Cat Patio / Deck) · More Info

Thank you

IMO plexi and from time to time remove and clean or get a nice big cage for the cat .

Screen in the balcony. They do it all the time on multi-story buildings will approval.

Wow - no one said, don't let the cat out on the balcony! At least, not unsupervised...

Who is in charge, you or your cat?

A curious cat could jump to the top of that rail, so I assume you need something that goes all the way up? Unlike trying to create a barrier for a small dog.

It's not that high. Your cat will survive a fall and it will probably teach her a lesson. My cat fell off a 7th story balcony with no broken bones. She was a bit sore for a day or two. (She slipped through the door and got onto it when I wasn't looking, I did not think a not-yet-screened 7th floor balcony was a safe place for a cat).

You didn’t share the patio dimensions, but have you considered placing a catio out there?

Here is a link to electric fences at chewy. Or you could try a short leash when she’s out there, but make it so she can’t fall over the balcony and hang.

https://www.chewy.com/b/fence-systems-455

A collar and a leash.

I had a cat jump off a balcony. He was uninjured, but had a "What the hell did I just do?" look on his face when he landed. He did not repeat.