3x the rent as a revenue and 3 month deposit is also standard in Switzerland. However, the deposit is put in a special account and the bank releases it when you move out. It is not that easy for the landlord to get a part of it. About the rent not exceeding one third of the revenue, it's of course not always easy to do, but if you exceeded it, you would risk having other financial problems which wouldn't be good for you neither.