A rental guarantee is an amount corresponding to one, two or three months' rent (maximum), which is used to guarantee payment of your rent in the case of a problem when you leave.

This amount is returned to you in full on your departure if no problems are identified by your estate agent.

The rental guarantee must be deposited in a bank account in the tenant's name.
This account is blocked and no one can touch it without official notification to the bank.

A guarantee such as that offered by a bonding service (e.g. SwissCaution, Firstcaution, SmartCaution, etc.) replaces a bank deposit for a rental guarantee, saving you the trouble of blocking this money in an account.