Bringing a New Roommate Into Your Shared Flat: What the Landlord Can Actually Demand

When a room opens up in an existing shared flat, the question comes up fast: can the remaining lead tenants simply move a new roommate in, or does the landlord have to agree? The answer depends on Section 553 BGB and a line of court rulings that give shared-flat residents a stronger right in this situation than many landlords realize in practice.

The Legal Basis: Section 553 BGB

If a legitimate interest in taking on another person arises after the lease is signed, the tenant can demand that the landlord allow subletting part of the living space. Moving out of the existing shared-flat setup and looking for someone to cover the vacated rent counts as exactly that kind of legitimate interest. Under Section 553 BGB, the landlord can only refuse permission if there's an important reason relating to the new roommate personally, if taking them on would overcrowd the apartment, or if subletting would otherwise be unreasonable for the landlord for some other important reason. If the landlord wants a higher rent in exchange for permission, they can only demand it if subletting would otherwise be unreasonable for them.

What Case Law Adds on Top of That

Beyond Section 553 BGB, the Berlin Regional Court ruled on 28 August 2013 (case no. 65 S 78/13) that a landlord who rents an apartment to a shared flat has to expect the group of residents to change over time — through relocation, training, or studies. From that, the court derived a standalone right for shared flats to swap members: when the remaining tenants request approval for a roommate change, giving the name and current address of the new person, the landlord has to respond promptly and can't refuse consent without a specific, case-by-case reason. In the case the court decided, the landlord hadn't responded for months; the court treated that as the absence of any legitimate interest in refusing.

The Right Way to Handle It in Practice

The request for approval should be made in writing and include the name, date of birth, and current address of the person moving in. It's also common and legally permitted for the landlord to ask for details on employment and income — typically as a self-disclosure form or a SCHUFA credit report — to assess the new person's creditworthiness. If the landlord doesn't respond within a reasonable period, follow up in writing and set a deadline for a response, rather than letting the person move in without approval. An unauthorized sublet can give the landlord grounds for termination, even though a court can later overturn such a termination if it turns out the landlord refused or dragged out approval without good reason — as this English-language overview of the tenant's right to sublet also lays out.

The Difference From a Full Tenant Swap

It matters to distinguish this from the situation where an existing lead tenant leaves the lease entirely and is replaced by the new person. That's no longer a straightforward sublet under Section 553 BGB — it's a contract amendment, which the landlord also has to approve, typically as an addendum to the lease. In practice, the two can be combined: the new roommate first moves in as a subtenant with approval under Section 553 BGB, and the formal step to lead tenant is documented in the contract afterward, once everyone agrees. Our PDF checklist for a shared-flat lease shows how a shared-flat lease can address this case in advance.

Conclusion

A landlord can't refuse a new roommate in an existing shared flat without a reason. Section 553 BGB gives shared-flat members a claim to approval once a legitimate interest exists, and the Berlin Regional Court's case law reinforces that right further, as long as the landlord is kept promptly and verifiably informed with reasonable details about the new person. Our guide to shared-flat leases covers the basics and every resident's obligations, and if you want to know how the deposit gets split when a roommate moves out, that's covered in a separate article. The tax side of subletting is explained in our piece on the shared-flat lease template. If you're still looking for the right shared flat or apartment, Waitly gives you a structured way through current listings — search here.

Frequently Asked Questions

Does the landlord have to approve every new roommate?

No, but they can only refuse for a specific, important reason relating to the person, or because of overcrowding. A blanket refusal without any reason isn't enough under Section 553 BGB and the case law built on it.

What documents can the landlord ask for about the new roommate?

Typically name, date of birth, current address, and details on employment and income — often as a self-disclosure form and a SCHUFA report. This lets the landlord assess the new person's creditworthiness.

What happens if we move the person in without approval?

That counts as an unauthorized sublet and can give the landlord grounds for termination. Courts have sometimes overturned such terminations where the landlord refused or dragged out approval without good reason, but it's safer to get written approval beforehand.