A rent increase when tenants change is permitted in Switzerland as a matter of principle. However, new tenants can challenge the initial rent before the competent conciliation authority within 30 days of taking over the apartment, if the conditions under Art. 270 of the Swiss Code of Obligations (CO) are met.
| Topic | Short answer |
| Basic rule | Increase permitted when tenants change |
| Deadline to challenge | 30 days from taking over the apartment (usually the key handover) |
| Requirement (one of two suffices) | Constrained position when signing the contract, or a considerable increase over the previous rent (court practice: more than 10 percent) |
| Additionally required | Abusive rent under Art. 269 CO (excessive yield or above the level customary in the locality and neighbourhood) |
| Competent body | Cantonal conciliation authority |
| Disclosure duty | Mandatory official form in 7 cantons (BE, BS, FR, GE, LU, ZG, ZH), partially in NE and VD; elsewhere disclosure on request |
| New since 1 October 2025 | The form must state the reference interest rate and inflation level on which the previous rent was based |
May the landlord raise the rent when tenants change?
The landlord may set the rent afresh with every change of tenant, because no rent protection carries over from the previous tenancy when a new rental agreement is concluded. The Swiss Code of Obligations gives landlords considerable latitude on a new contract. Tenants are not without protection, however, because Art. 270 CO gives them a right to challenge.
This latitude explains why landlords use tenant changes for increases more often than ongoing tenancies. A rent adjustment during an ongoing tenancy is subject to stricter formal requirements: it requires an official form, is tied to a termination date, and must be challenged by the tenant within 30 days of notification if they want to contest it (Art. 270b CO). When tenants change, these hurdles fall away. Housing shortages amplify this effect, as landlords sometimes raise the rent considerably at a change of tenant without making any value-adding investments. An initial rent increased in this way can be abusive and therefore contestable. The Swiss Tenants’ Association (Mieterinnen- und Mieterverband, MV) advises actively asking for the previous rent and checking the increase arithmetically before the 30-day deadline expires.
Does the landlord have to disclose the previous rent?
Whether the landlord must disclose the previous rent unprompted depends on the canton, but on request a duty to inform applies throughout Switzerland under Art. 256a para. 2 CO. Anyone who does not know the previous rent cannot assess the increase and therefore cannot make targeted use of their right to challenge.
According to the register of the Federal Office for Housing (BWO), a mandatory official form applies in these cantons, meaning the landlord must state the previous rent unprompted on an official form:
- Canton of Basel-Stadt
- Canton of Bern (since 1 December 2025)
- Canton of Fribourg
- Canton of Geneva
- Canton of Lucerne
- Canton of Zug
- Canton of Zurich
- Canton of Neuchâtel (partially: only apartments with 2 to 5 rooms)
- Canton of Vaud (partially, depending on the vacancy rate in the district)
In all other cantons, tenants have to ask actively. The landlord is then obliged to provide the information under Art. 256a para. 2 CO. Since 1 October 2025, an extended duty also applies: the disclosure form must now additionally state the reference interest rate and the level of the national consumer price index (CPI) on which the previous rent was based. Anyone using an outdated form after this date risks the agreement on the initial rent being void. These details make it easier to check whether the new rent can be objectively justified. The Federal Office for Housing (BWO) publishes the reference interest rate quarterly, providing the comparison basis tenants need for this check.
When does challenging the initial rent stand a chance of success?
A challenge to the initial rent stands a chance of success if one of two admissibility requirements under Art. 270 CO is met and the rent is additionally abusive within the meaning of Art. 269 CO. The two requirements are alternatives, so one of them is enough:
- Requirement A, constrained position when signing: The tenant felt compelled to sign the rental agreement because of personal or family hardship or because of conditions on the local housing market.
- Requirement B, considerable increase: The landlord raised the initial rent considerably compared with the previous rent. Under Federal Supreme Court practice, an increase of more than 10 percent counts as considerable.
- Additional condition under Art. 269 CO: The rent must be abusive, i.e. it yields an excessive return or lies above the level customary in the locality and neighbourhood for comparable properties. At this stage the landlord can justify the increase, for example with value-adding investments such as a renovation.
Important: A challenge is also possible after the rental agreement has been signed. The 30-day period runs from taking over the apartment, usually the key handover, not from signing the contract. You can use the rent calculator of the Swiss Tenants’ Association (MV) to get a first assessment before you approach the conciliation authority.
A common counter-argument is fear of termination after a challenge. Art. 271a CO explicitly protects tenants here: a termination issued because the tenant asserts claims arising from the tenancy is contestable. Anyone already living in an ongoing tenancy who considers the rent too high can also apply for a rent reduction.
Step by step: how to challenge the initial rent
Anyone wishing to challenge the initial rent must complete three steps within 30 days of taking over the apartment. The deadline is absolute: once it has passed, a challenge to the initial rent is excluded.
Step 1: Find out the previous rent
Approach: Contact the landlord in writing and ask for the previous rent and the reference interest rate on which it was based. In cantons without a mandatory form, the duty to inform under Art. 256a para. 2 CO applies.
Tip: Send the request by registered letter or by email with a read receipt so that you have proof.
Step 2: Calculate the increase and check the grounds
Approach: Calculate the percentage difference between the previous rent and your new rent. If it exceeds 10 percent, the increase counts as considerable under Federal Supreme Court practice, and the admissibility requirement under Art. 270 CO is met. Whether the rent is also abusive is then clarified by the conciliation authority.
Tip: The rent calculator of the Swiss Tenants’ Association (MV) supports the calculation. If unsure, personal advice from the MV is recommended before you act.
Step 3: File the application with the conciliation authority
Approach: File the challenge in writing with the cantonally competent conciliation authority. The 30-day period from takeover is absolute and continues to run even while you are still negotiating with the landlord.
Tip: File the conciliation application on time even if talks with the landlord are ongoing. Ongoing negotiations do not suspend the deadline.
After filing
The conciliation authority summons both parties to a hearing. If the parties reach agreement, a settlement is recorded. If no agreement is reached, tenants can take the matter to the competent tenancy court. For the hearing, prepare the rental agreement, all correspondence with the landlord and the written information on the previous rent. Presenting these documents in full makes the assessment considerably easier for the conciliation authority and shortens the hearing.
Frequently asked questions about rent increases when tenants change
Which grounds justify a rent increase?
The landlord may raise the rent if the reference interest rate has been increased, inflation measured by the CPI has risen, maintenance and operating costs have actually increased, or larger value-adding conversions and renovations have taken place. When tenants change, no legally prescribed ground is required for the increase. Tenants can nevertheless challenge the initial rent if the conditions under Art. 270 CO are met.
May the landlord raise the rent for the next tenant?
Yes, the increase is permitted in principle. The incoming tenant also has a 30-day right to challenge from taking over the apartment under Art. 270 CO. What matters is whether the new rent is abusive within the meaning of Art. 269 CO. As a rule of thumb: an increase of more than 10 percent over the previous rent without any recognisable consideration in return, such as a renovation, is a clear signal to challenge.
What happens to the rental agreement if the landlord changes?
If ownership changes through a transfer of title, the new owner steps into the existing rental agreement (Art. 261 CO). The rent remains unchanged, because under the principle of Swiss tenancy law that a sale does not break a lease, all rights and obligations from the ongoing agreement pass to the new owner. Tenants do not have to renegotiate the existing rent. A later increase during the ongoing tenancy must be notified by the new owner using the official form and with effect from a termination date.
What should be considered when tenants change?
When tenants change, tenants should ask for the previous rent, calculate the percentage increase and keep the 30-day challenge period from takeover in view. The handover report must be checked and documented carefully. All the information about your rental agreement in Switzerland helps you stay on the safe side from the start. Depending on the canton, it is also worth checking whether the form requirement applies and whether the disclosure form is complete.
