Rental Contract
In general, landlords sign a written rental contract with their tenants. It is possible to agree on an oral contract. However, this is not recommended. In any case, the rights and duties according to the Swiss Code of Obligations (Obligationenrecht | Droit des obligations) are always applicable.
Links
ch.ch / additional information (EN)
Schweizerische Kriminalprävention / Housing Search Fraud (DE | FR)
Documents
Example "Rental Contract" (DE)