Subletting legally: permission first, always

Subletting without your landlord's permission is a serious breach of contract and can end in immediate termination of your lease. But German law does offer protection to tenants in one key scenario: when renting out part of your flat, you often have the legal right to demand the landlord's consent if you have a legitimate reason. Full subletting of the whole apartment and short-term holiday rentals via Airbnb are different stories entirely, with significantly fewer protections and far greater legal risks.

Partial subletting: the tenant-friendly exception

If you want to rent out a room in your apartment while you continue to live there, German law gives you a strong position. Under Section 553 of the BGB (German Civil Code), a tenant who rents out part of the apartment has the legal right to demand permission from the landlord. But this right only exists if you have a legitimate interest.

What counts as legitimate interest

A legitimate interest is a reason for subletting that arose after you signed your original rental contract. German courts recognize both personal and economic reasons. Common examples include a partner moving out and needing to cover the full rent yourself, losing your job and struggling with housing costs, or needing temporary extra income. In shared flats, accepting a new subtenant when your previous roommate moves away is also considered legitimate interest.

One critical condition: you must actually live in the apartment you are subletting. You can take business trips or holidays lasting several months, but you cannot move out for years and claim partial subletting rights. The apartment must still be your home, at least in part.

What happens if the landlord refuses

If you have legitimate interest and the landlord refuses permission without good reason, you have legal remedies. You can take the landlord to court to force them to grant permission. Some tenants have even won compensation for lost rental income, though this requires legal action. A landlord can refuse only if there are specific grounds, such as the apartment becoming overcrowded, concerns about the subtenant's suitability, or genuine unreasonable burden.

Full subletting of the entire flat

If you plan to sublet your entire apartment and move elsewhere, the legal situation is fundamentally different. Under Section 540 of the BGB, you need the landlord's permission before subletting the whole flat. However, unlike partial subletting, the landlord can refuse this permission freely and does not need to provide any reason. A temporary absence from the city does not automatically grant you the right to sublet the entire property.

This is a critical distinction: while partial subletting carries a tenant-friendly legal right, full subletting depends entirely on the landlord's goodwill. Many landlords refuse because they lose direct control of their property and the relationship with the occupant. Some rental contracts explicitly prohibit full subletting or require separate written permission to be granted in advance.

The profit trap: you cannot make money by subletting

A landmark 2026 ruling by Germany's Federal Court of Justice (BGH) clarified a crucial rule: subletting is allowed only to cover your housing-related costs, not to generate profit. The case involved a tenant in Berlin paying 460 euros per month in rent but charging his subtenant 962 euros per month for the same apartment. The court confirmed this was unlawful and upheld the landlord's termination of the main lease.

What does this mean in practice? You can ask your subtenant to pay a share of rent, utilities (Nebenkosten), and heating costs. If your apartment is furnished, a modest surcharge to cover the depreciation of furniture may be permitted. But any attempt to extract significant profit—especially renting at market rates in tight housing markets—can be grounds for termination.

In some tight rental markets like Berlin, rent control rules also apply to subleases. This adds another layer of legal restriction on how much you can charge.

The Untermietzuschlag: what rent increase is permitted

When you sublet, Section 553 of the BGB allows your landlord to demand a reasonable surcharge to your own rent. This is called the Untermietzuschlag. However, the landlord must raise this with you in writing before you and the subtenant finalize the arrangement. You have the right to refuse a surcharge you consider unreasonable, but if you do, the subletting cannot proceed.

The surcharge is typically limited to compensating the landlord for increased utilities and wear and tear caused by an additional occupant. A common benchmark is up to 20 percent of the subtenant's rent or up to 10 percent of your own net rent, whichever is lower. For furnished apartments, the landlord may also claim a reasonable depreciation-based surcharge for the furniture, but this must be calculated transparently and not used to hide profit-taking.

Short-term rentals and Airbnb: Zweckentfremdung rules

Subletting a room for a few weeks is one thing; renting out your apartment via Airbnb is quite another. Many German cities have enacted Zweckentfremdung laws (laws against misuse of residential housing), which strictly regulate short-term tourist rentals. These are municipal rules, not federal law, which means regulations vary significantly by city and district.

Berlin's strict rules

Berlin has some of Europe's strictest short-term rental regulations. Under the Zweckentfremdungsverbotsgesetz, you cannot rent out residential apartments as holiday accommodations without a permit. The only exception is if you live in the apartment as your primary residence (registered via Anmeldung) and rent it out for a maximum of 90 consecutive days per year. Even then, you must obtain and display a valid Registriernummer (registration number) from your local Bezirksamt.

Second homes are banned from short-term rental entirely. If you violate these rules, fines can reach up to 500,000 euros. Both the host and the platform (Airbnb, Booking.com, etc.) can be fined. Berlin actively enforces these rules through district offices that monitor listings and investigate complaints.

Other major cities

Munich allows short-term rentals of your primary residence for a maximum of 56 days per year. Hamburg has similar restrictions with its own registration system (Wohnraumschutznummer) and fines up to 100,000 euros. Other smaller cities may have looser rules or no Zweckentfremdung law at all, but many are tightening regulations as housing pressure increases.

The crucial point: short-term rental laws are a patchwork across Germany. Your city or even your district may have unique requirements. Always check your local municipality's website or contact your Bezirksamt before listing anything on a holiday rental platform.

How to sublet correctly

Step 1: Get permission in writing

Never sublet without written permission from your landlord. While German law recognizes oral contracts, if a dispute arises you would have to prove that the landlord consented. In practice, the burden of proof can be very difficult. Send a formal letter to your landlord stating clearly that you wish to sublet part (or all) of the apartment, and explain your reason. Include the proposed rental period, rent amount, and details of the intended subtenant if you have them.

If the landlord agrees, ask for a written response. If the landlord proposes an Untermietzuschlag, get that in writing too, and make sure you agree to the amount before proceeding.

Step 2: Draft a sublease contract

Once you have the landlord's written permission, create a formal sublease contract (Untermietvertrag) with your subtenant. This contract should specify the rental period, the amount of rent and utilities, payment terms, the subtenant's security deposit (Kaution), and each party's responsibilities for maintenance and repairs. Many online templates and tenant associations offer sample contracts.

Make clear in the contract that you are the main tenant and the subletting is temporary. Specify a clear end date or, if open-ended, what notice period either party must give to terminate the arrangement. Collect a security deposit from the subtenant to protect yourself against damage or unpaid rent.

Step 3: Register the subtenant

If your subtenant will live in the apartment for more than three months, they must register their address with the local Bürgeramt (citizenship office) via Anmeldung. Failure to register can result in fines for the subtenant. As the main tenant, you should ensure this registration happens and verify that it has been completed.

Step 4: Handle taxes

Any income from subletting must be declared to the Finanzamt (tax office) as part of your income tax returns. Keep records of all rental payments. If you are a non-resident or resident with a Steuer-ID, you must report this income. Consult a tax advisor if you are unsure about your obligations, especially if you are an expat or student.

What happens if you sublet without permission

Subletting without the landlord's permission is a breach of contract. If your landlord finds out, they can issue a written warning and demand that you end the subletting. If you ignore the warning and continue, the landlord can terminate your main rental contract without notice—this is called Kündigung without Einhaltung einer Frist (termination without a notice period). You would then be required to vacate the apartment, and the subtenant would also have to leave.

The severity of the consequence depends on the circumstances. A landlord must usually give a written warning first, which gives you a chance to end the subletting and save your lease. But if you have already breached the contract by subletting the entire apartment without permission or if you engage in profit-driven subletting, the landlord's position is much stronger.

Key takeaways

• Partial subletting (renting out a room while you live there) is your most protected scenario. If you have legitimate interest, the landlord must usually consent.
• Full subletting requires explicit landlord permission and can be refused for any reason or no reason.
• Subletting must cover costs only—profit-driven subletting is illegal and can lead to termination of your lease.
• Get all permission from your landlord in writing, and draft a clear written contract with your subtenant.
• Short-term holiday rentals (Airbnb, Booking.com) are heavily restricted by Zweckentfremdung laws in most major cities. Always check your local rules and get explicit permission.
• Register your subtenant with the Bürgeramt if they are staying more than three months.
• Declare subletting income to your Finanzamt.