The answers to your questions ...
What must be written in a rental agreement? How high may the rent deposit be? How do I defend myself against a rent increase? What should I do if my new partner wants to move in with me? Which repairs in the apartment do I have to pay for at my own expense? These are just some of the questions that can arise in the course of a tenant's life. If you are not familiar with them and don't know which advisory and mediation bodies can help you, the issues provide fertile ground for disputes between tenants, with the landlord, the administration or the janitor, which can often last for years. A stressful situation for almost everyone, which can usually be avoided through knowledge and education.

... can be found here:
Download here the jointly published by the Tenants Association, Homeowners Association, the Association of Housing Cooperatives and many other relevant representatives in this field information "Living in Switzerland " free of charge as a PDF, keep it and refer to this reliable guide in case of uncertainty.