Allow or Refuse Untervermietung? Landlord Guide (2026)
Allow or Refuse Untervermietung? Landlord Guide
For part of the flat with a legitimate interest you must, as a rule, allow it (§ 553 Abs. 1 BGB).
You may refuse only for good cause, overcrowding, say, or something in the third party's person, and you may require a reasonable sublet supplement. You never have to permit the whole flat.
§ 553 BGBIn 60 seconds
Where the tenant sublets only part of the flat and has a legitimate interest that arose after the tenancy was signed, they have a right to permission (§ 553 Abs. 1 BGB).
You may refuse only for good cause: something in the third party's person, threatened overcrowding, or other unreasonableness (§ 553 Abs. 1 S. 2 BGB).
Refuse wrongly and the tenant may terminate early on the statutory notice period (§ 540 Abs. 1 S. 2 BGB) and may have a damages claim against you, for lost sublet income, for instance.
Letting the whole flat without your permission is a ground for termination: warn, and on continued unauthorised use terminate without notice (§ 543 Abs. 2 S. 1 Nr. 2 BGB).
Under the case law, commercial short-term letting generally does not establish a legitimate interest.
What the law says
Where a legitimate interest arises for the tenant after the tenancy is concluded in letting part of the dwelling to a third party, they may require the landlord's permission; not so where there is good cause in the third party's person, where the dwelling would be overcrowded, or where it is otherwise unreasonable. Where permitting it is only reasonable against an appropriate increase in rent, the landlord may make permission conditional on that. Working translation; the German original is the binding text.
What you must and what you may
| Situation | Must you permit it? | When may you refuse? |
|---|---|---|
| Part of the flat, legitimate interest arising after signature (§ 553 Abs. 1) | yes. The tenant has a right | only for good cause: the third party's person, overcrowding, unreasonableness |
| Part of the flat, only reasonable with a rent increase (§ 553 Abs. 2) | yes, against a reasonable supplement | where the tenant refuses the reasonable supplement |
| The whole flat (§ 540 BGB) | no, no legal right | at your discretion; letting without permission is a ground for termination |
| Commercial short-term letting | no, regularly no legitimate interest | always; without consent it is unauthorised use |
The sublet supplement: when you may charge more
Where permitting the sublet is only reasonable against an appropriate increase in rent, you may make permission conditional on it (§ 553 Abs. 2 BGB). The measure is the actual added burden, higher operating costs from an additional occupant, for instance, not a figure you would like and not a flat percentage of the base rent.
If the tenant refuses a reasonable supplement, you may refuse permission. But demanding an excessive or flat-rate supplement is equivalent to refusing without cause.
What it means for each side
- For part of the flat you have a right where a legitimate interest exists.
- Name the person, the rooms and the period in your request.
- Check any supplement demanded for proportionality.
- On a wrongful refusal, the special right to terminate may apply (§ 540 Abs. 1 S. 2 BGB).
- Establish first whether it is part of the flat or the whole of it.
- Assess the legitimate interest: did it arise after signature and does it carry weight?
- Make permission conditional on a supplement only where letting is otherwise unreasonable for you.
- Decide in writing and provably, with reasons where you refuse.
Common mistakes
For part-subletting with a legitimate interest there is a right. Refusing without good cause can trigger a special termination and damages.
It must reflect the actual added burden (§ 553 Abs. 2 BGB), not a figure you would like.
The right to permission covers part only; you never have to permit the whole flat.
Unauthorised subletting normally requires a warning before termination without notice (§ 543 Abs. 3 BGB), and the decision belongs on record.
What to do next
Assess the request: who is moving in, for what period, part or whole flat?
Assess the legitimate interest. Did it arise after signature and does it carry weight?
Check for good cause: the third party's person, overcrowding, unreasonableness.
Decide in writing, with reasons on a refusal, naming the person, the period and any supplement.
Frequently asked questions
Must I allow the Untervermietung (subletting)?
For a part of the flat, usually yes: if your tenant has a berechtigtes Interesse (legitimate interest) that arose after the contract was signed, they have a claim to the Erlaubnis (§ 553 Abs. 1 BGB). For the whole flat there is no such claim, that requires your express consent (§ 540 BGB), which you may withhold.
When may I refuse the Untervermietung?
Only for a wichtiger Grund (good cause) under § 553 Abs. 1 Satz 2 BGB: if there is good cause in the person of the Untermieter, if the flat would be overcrowded (Überbelegung), or if the arrangement is otherwise unreasonable for you. A refusal without good cause is unlawful and can entitle the tenant to a Sonderkündigung (special termination) and damages.
May I charge an Untermietzuschlag (sublet surcharge)?
Yes, if the arrangement is reasonable for you only against a reasonable rent increase (§ 553 Abs. 2 BGB). In practice a surcharge of roughly 10 to 20 percent of the rent attributable to the Untermieter is considered reasonable. A flat surcharge without a factual basis is not permitted.
What can I do about unauthorised Untervermietung?
If the tenant lets the flat to a third party without your Erlaubnis, they breach the contract. You may issue an Abmahnung (formal warning) and, on continued unauthorised use, terminate with or without notice (§ 540, § 543 Abs. 2 Nr. 2 BGB). A fristlose Kündigung (termination without notice) normally requires a prior Abmahnung.
Is subletting via Airbnb allowed?
Short-term, profit-oriented letting to changing guests regularly does not constitute a berechtigtes Interesse under § 553 BGB according to BGH case law. You need not permit it; done without consent, it is unauthorised use and can lead to Kündigung.
May I limit the Erlaubnis or attach conditions?
Yes. You can limit the Erlaubnis to a named person for a defined period and make it conditional on a reasonable Untermietzuschlag (§ 553 Abs. 2 BGB). You need not grant permission 'for an unknown person'. The tenant must name the Untermieter.
This page gives general information as at the date shown. It does not replace legal advice on an individual case.