@giuseppebilotta This is one very strange cat. Fancy using the chair reserved for it instead of occupying chairs (or draws or desks or storage containers or flower pots or ...) that you don't want it to use!
If we placed such a sign on our cat's favourite resting spot, it would no doubt react in anarchic disgust and decamp to a more unconventional location.
I mean really, it's almost as weird as a cat playing with its designated toy.