Tenants in a shared apartment, studio with shared kitchen and furnished studio with shared kitchen will be given one key each and no additional keys will be available. In other types of apartments, it is possible to buy one additional key (with the exception of apartments reserved for exchange students). The cost of an extra key will be charged according to the tenant charge sheet.
The amount you have paid for an additional key will not be refunded when you move out. If you have a school age child living in the apartment, you can have the additional key free of charge. Having additional keys made yourself is strictly forbidden. For security reasons, any unauthorised additional keys may mean that the lock has to be rekeyed, and the tenant will be charged for that according to the tenant charge sheet.