the cpf number   is always required, and in case of foreigners their proof of legal residence (registro nacional de estrangeiros - rne) number is necessary as well.

additionally, a potential tenant must show paystubs proving that monthly earned income is three times the monthly rent, or bank statements if self-employed, and the imposto de renda das pessoas físicas (irpf), which is the brazilian personal income tax declaration. 

in certain cases, these documents may not all be necessary if a potential tenant is renting directly from property owners, or in case of subletting - room renting typically does not require all these documents as well. 

the standard tenancy contract in rio, is called a  contrato de locação de imóvel, is a requirement before renting a property in the city, and needs to be signed by both the tenant, and the real estate agency or the owner.