I think it should be left to have pets like dogs, birds or cats, for example. The person renting the apartment should reach an agreement with the owner who has rented to give him permission to take the floor to their pets, ie reach an agreement that benefits them both. It is true that animals get dirty a lot, it is normal, but with good care and constancy, this need not be a problem. It is true that there is a law which do not let the floors of the city there are animals, which seems to me unfair, having an animal at home makes the atmosphere is cheerful and lose the silence there on a floor if the person living in it lives alone. In short, I think it would be better to have pets in an apartment, but with constant care, and on the other hand, the law should not prohibit having animals in an apartment, you take away the joy of having one of the best companions floor that we could have, maybe even the best.