Subletting a spare room is a popular way to cut housing costs in expensive German cities. However, subletting without the landlord's permission can justify terminating your tenancy, in some cases without notice.

The tenant's right to sublet part of the flat (Section 553 BGB)

If, after the contract is signed, you develop a legitimate personal or financial interest (for example a partner moving in, a drop in income or a long business trip), the landlord must consent to you subletting part of the flat, provided this does not lead to overcrowding.

The landlord's written permission

Ask the landlord for permission in writing, giving your reasons and the details of the future subtenant. Letting to tourists through platforms such as Airbnb requires a permit in many cities (Zweckentfremdung); violations are punished with high fines.

Drawing up a sublease (Untermietvertrag)

The relationship between the main tenant and the subtenant is governed by a separate sublease. It sets out the room being let, the shared use of kitchen and bathroom, the flat-rate contribution to service charges and the notice rules.

Tax on income from subletting

If the sublet rent exceeds your actual proportionate costs for that part of the flat, you make a surplus that you declare in Annex V (Anlage V) of your tax return. If the rent only covers your share of the costs, there is no taxable surplus.

What to check

  • Ask the landlord for permission in writing and provide the subtenant's details.
  • Sign a detailed written sublease with an inventory.
  • Issue the subtenant with a landlord's confirmation (Wohnungsgeberbestätigung).
  • Keep all payment records to show the tax office that you make no profit.

Example situation

The tenant of a three-room flat asks the landlord, citing Section 553 BGB, for permission to sublet a room to a colleague, receives it a week later and saves €550 a month.

Next step

Subletting part of your flat is legal with the landlord's permission; never sublet in secret.

Official information on this topic

Checklists and examples are organisational recommendations. Requirements depend on the procedure, the city and your situation; check them with the relevant office before you act. Please discuss legal and tax questions with an authorised professional.

This article was prepared with the help of AI. The example illustrates the approach and does not describe a client case.