For your viewing pleasure : https://imgur.com/gallery/CsfBWHz
Maybe some better camera angles next time
I'm very pleased to announce that the auto cat sprayer worked last night .. Twice.. !!
Orange peel works for my neighbors. We have roof cats here in Bern who love to poop on balconies. They just come to mine for pets though.
Many thanks to everyone for sharing your cat wisdom. I spoke to the neighbours and mentioned the 100 franc dry cleaning bill for my duvets. They did not offer to pay. They explained that the cat doing the peeing was in heat. She needed to be spayed, but the vet was closed due to the lockdown. The neighbours have put some very inadequate bamboo fencing round their balcony, which doesn't stop the cats at all.
I went away for the summer, and now I'm back, the cats are up to their tricks again. They come into my flat through the balcony door when my back is turned and hide in various places. One of them peed on my sofa again last night; I think it got shut into my flat when I locked up for the night.
I am going to buy a cat gate and install it on the French doors to my balcony (it's a small flat and my sitting room has no other windows, so I have to keep these doors open, especially in hot weather).
Gently shooing them away is something I have tried repeatedly. They don't care. I have fired a water pistol at them. They don't care. They are terrified of me and have been since day 1, but that doesn't deter them from coming into my flat.
I love cats and sympathise with people who want to keep them, but as an animal lover, it doesn't seem right to me to keep 2 dogs and 2 cats in a small 2 bedroom 4th floor flat. However, that's not my call.
I admit I did not read the whole thread .....
Two dogs and two cats in a 3-room apartment could be the explanation the cats invade your flat.
You need to inform the property management. Keeping pets is usually only allowed as long as they don't cause major problems and this is a problem which can easily be solved with proper cat-nets. (I had to install them once as my balcony was within the roof and my loved ones would have loved to roam them and escape , these nets work very well).
I had a neighbour once who kept 21 cats in a 2.5 room flat (I.am.not.joking) and of course her cats jumped over to my balcony and got mine all flustered as they were basically wild cats (21 cats and one human - it's cats rules). In addition those cats were never able to jump back (never found out why not) so I had to catch these wild animals when I came home at nights and bring them back. It was the janitor who started counting cats on the balcony, then asked me whether it was possible there were 18 cats there .... I didn't have the heart to tell her it was actually 21 .
However, I think animal protection was involved, the lady moved out and I couldn't work for two days (home office in those days) because they had to sand off the parquet and phoning customers was impossible with that noise. Had it been a cheaper parquet it would have to be replaced totally (cat pee etc).
So long story short: It is not in the interest of the owner for tenants to have too many pets on too little room. It is also the pet owner's duty to keep in door cats in check (out door cats is a different story - the are free spirits ).
On the 4th floor the only thing you should be dealing with is birds - I take it you have no such problem there at the moment.
Write a registered letter about it to property management, mention what you've done so far, the reactions you got, the amount of animals in your neighbour's flat, and give them a date by which you want the problem solved. Mention that your flat under these conditions is not worth it's rent.
Thanks for your answer - it spoke from experience and was really informative. I'm happy to report that my neighbours have put a cat cage round their balcony, and I haven't had any little visitors since. I'm really grateful that they took the responsibility of solving the problem.