Your Frankfurt Landlord Announces a Renovation: The 8 Percent Rule, Your One-Month Window and Milieuschutz
After a qualifying modernisation your Frankfurt landlord may raise the yearly rent by 8 percent of the costs spent on your flat (§ 559 BGB), not 11 percent as older guides still say, and the monthly rent may rise by no more than 3 euros per square meter within six years (2 euros if your rent was under 7 euros per square meter). A new heating system is capped at 0.50 euros per square meter. You must be told in writing at least three months before work starts, and your two clocks run until the end of the month after the letter arrives: the hardship objection and the special termination right. In Frankfurt's milieu-protection areas the city also has to approve many works, and it writes to the affected tenants first.
What the Law Allows, and What Older Guides Get Wrong
If you rent in Frankfurt and a letter announces insulation, new windows, a lift, a bathroom or a new heating system, two separate things follow. Your landlord can increase the rent afterwards, and you have a short window to respond now. Both are governed by the Civil Code, with Frankfurt-specific rules on top in the city’s milieu-protection areas.
The central rule is in § 559 BGB. After qualifying measures the landlord may raise the annual rent by 8 percent of the costs spent on your flat. Plenty of older guides still say 11 percent. The current text says 8.
Qualifying measures include work that saves final energy, saves water, raises the use value of the property, lastingly improves general living conditions, or that the landlord had to do for reasons beyond their control. Two deductions apply before the 8 percent:
- Costs that would have been needed for ordinary maintenance do not count (§ 559 Absatz 2).
- Costs paid by tenants or covered by public budget funding, and the benefit from subsidised loans, are deducted (§ 559a BGB).
The euro cap
Whatever the percentage gives, the monthly rent may not rise by more than the cap within six years, not counting normal increases up to the local comparative rent.
| Situation | Cap per square meter of living space | Example, 60 square meters |
|---|---|---|
| Rent before the increase is 7 euros per square meter or more | 3 euros within six years | 180 euros a month |
| Rent before the increase is under 7 euros per square meter | 2 euros within six years | 120 euros a month |
| Installing or setting up a heating system | 0.50 euros within six years | 30 euros a month |
For heating systems, § 559e BGB adds a separate rule of 10 percent of the costs after subtracting public funding, with the same 0.50 euro cap. Heating law has been moving, and the BGB text now names the Gebäudemodernisierungsgesetz, so check which provision your landlord’s letter uses.
A worked example (illustration, not Frankfurt data)
Suppose the landlord spends 12,000 euros on your 60 square meter flat and 20 percent of that would have been maintenance anyway. That leaves 9,600 euros. Eight percent is 768 euros a year, or 64 euros a month, about 1.07 euros per square meter. That is under the 3 euro cap, so it is allowed.
The simplified procedure in § 559c BGB works for costs up to 10,000 euros per flat and replaces the maintenance estimate with a flat 30 percent deduction. At exactly 10,000 euros that is 7,000 euros, times 8 percent, so 560 euros a year or about 46.67 euros a month. The price of the shortcut for the landlord is that, with limited exceptions, no further modernisation increase is possible for five years after the notice reaches you.
Your Clock Starts With the Announcement
Under § 555c BGB the landlord must announce the work in text form at least three months before it starts. The letter must describe the work in essential terms, name the expected start and duration, and, if a rent increase is planned, give the expected amount and future operating costs. The landlord should also tell you the form and deadline for a hardship objection. Trivial work with an insignificant rent effect is exempt.
Two deadlines run to the end of the month after the letter arrives:
- Hardship objection (§ 555d BGB). You report hardship circumstances in text form. A late objection can still be heard if you were prevented without fault and you report promptly. Hardship connected to the rent increase must be raised no later than the start of the work.
- Special termination (§ 555e BGB). You may terminate extraordinarily, and the lease then ends at the end of the month after next. A letter that arrives in March means notice by the end of April and the lease ends on 31 May.
During energy-saving modernisation, § 536 BGB says a loss of usability is ignored for three months for rent reduction purposes.
The Rent Increase Statement Itself
The increase has to be explained, not just announced. § 559b BGB requires text form, a calculation based on the costs incurred, and an explanation that meets §§ 559 and 559a. The higher rent is due from the start of the third month after the statement reaches you. That period grows by six months if the work was not announced properly or the actual increase exceeds the announced one by more than 10 percent. An agreement that puts the tenant in a worse position is void.
Put the announcement, the final statement and your own rent history side by side. Compare the announced cost with the final bill, the percentage, the cap and the date.
When the Landlord Plays Games
§ 559d BGB presumes a breach of the landlord’s duties if work does not begin within twelve months of the announced start, if the announced rent increase would at least double the monthly rent, if the work is done in a way likely to cause objectively unnecessary burdens, or if it stops for more than twelve months after starting. The presumption can be rebutted with an objective reason. If one of these fits, write it down and get advice.
Frankfurt: Milieuschutz and Where to Get Help
Frankfurt has 15 preservation statutes under which, according to the city’s January 2026 Merkblatt, works need approval even when they would otherwise need no permit. The areas listed include Dornbuschsiedlung, Alt-Eschersheim, Anne-Frank-Siedlung, Dichterviertel, the eastern Gallus, Bockenheim, Nordend-Mitte, Nordend-Süd, Berger Straße, the western Ostend, Gutleutviertel, Sachsenhausen-Nord and the western Riederwaldsiedlung. Check your exact address on planAS, as the city’s tenant-rights page describes.
| Measure | Approvable | Not approvable |
|---|---|---|
| Bathrooms | Up to 5 square meters | Over 5 square meters |
| New balconies, roof terraces, winter gardens | Up to 5 square meters | Over 5 square meters |
| Lift | If the Hessian building code requires it | If it is not required |
| Heating replacement | Irreparable or older than 30 years, or with the Frankfurt Modernisierungsbonus and its conditions | Repairable and not older than 30 years, without that funding |
| Insulation of outer parts | To the minimum standard of the energy law | Beyond the minimum without the funding |
Two points matter for tenants. First, before the city approves a modernisation in these areas, its Stabsstelle Mieterschutz writes to affected tenants and invites comments, with an info line at 069 212-37777. Second, the Modernisierungsbonus comes with conditions, such as use restrictions and the permitted rent after modernisation. Ask whether your building took that money.
Free and paid advice
- City advice. The Mietrechtliche Beratung of the Amt für Wohnungswesen, Adickesallee 67-69, advises Frankfurt residents free of charge if the monthly household net income does not exceed 2,150 euros plus 650 euros per further household member. Make an appointment on 069 212 34711 or by e-mail. There are no open consultation hours at present, and phone advice is on Monday, Wednesday and Friday 8:30 to 12:00, per the city’s page.
- Mieterschutzverein. The DMB Mieterschutzverein Frankfurt am Main is at Eckenheimer Landstraße 339, phone 069 5601057-0. Phone advice runs Monday to Thursday 9:00 to 12:00 and 14:00 to 16:00, Friday 9:00 to 12:00 and 13:00 to 15:00, on its contact page. Ask about the current fee and about any waiting period before its legal-protection cover applies to a new case, and join before a dispute starts, not during it.
- Court. Rental disputes about a flat go to the court of the district where the flat lies (§ 29a ZPO). The Amtsgericht Frankfurt am Main (Gerichtsstraße 2) has its civil divisions in the Außenstelle Niederrad, Hahnstraße 25.
Step by Step
- Date the letter.Keep the envelope. The hardship and special termination clocks run to the end of the next month.
- Check the three months.Is the start date at least three months after the letter arrived, and is the content complete?
- Check the address.In a Frankfurt milieu-protection area, look on planAS and ask the Stabsstelle Mieterschutz.
- Decide on hardship.Health, age, family and income reasons go in writing within the deadline.
- Decide on special termination.Only if moving is a real option.
- Wait for the increase statement.Check the cost basis, the 8 percent, the cap, the funding deduction and the due date.
- Get advice before you answer or pay the difference.City advice or the Mieterschutzverein.
Compliance Note
This page explains §§ 555b to 559e BGB and the Frankfurt rules on milieu protection as published in October 2026. The percentage, the caps and the heating rules have changed before and may change again, so check the current text. It is not legal advice. Deadlines in tenancy matters are short, and the right step depends on your lease, the letter and your finances.
FAQ & Common Pitfalls
Is the cap on modernisation rent increases 8 percent or 11 percent?
Eight percent. § 559 Absatz 1 BGB lets the landlord raise the yearly rent by 8 percent of the costs spent on the flat. The older 11 percent figure still appears in some English-language tenant guides and older articles, but it is not in the current text of the law. On top of the percentage there is a euro cap: the monthly rent may not rise by more than 3 euros per square meter of living space within six years, or 2 euros if the rent was below 7 euros per square meter before the increase.
My landlord is replacing the heating. Can the rent rise by 8 percent of that cost too?
Not freely. Heating-system installations have their own limit. § 559 Absatz 3a Satz 3 BGB caps the rise from such a measure at 0.50 euros per square meter per month within six years, and § 559e BGB adds a separate rule of 10 percent of the costs after subtracting public funding, with the same 0.50 euro cap. For a 60 square meter flat that is at most 30 euros a month for the heating part. The BGB text now refers to the Gebäudemodernisierungsgesetz for heating systems, so ask your landlord which provision the letter relies on.
Do I have to move out or stop paying rent during the work?
No. You must tolerate the measure unless it causes you or your household a hardship that is not justified, but you do not move out and you do not stop paying. For energy-saving modernisation, § 536 Absatz 1a BGB says a reduced usability of the flat is ignored for three months, so rent reduction is not available in that window. After that, a rent reduction for real defects is a separate question, and you should get advice before reducing.
What counts as hardship, and how late can I raise it?
§ 559 Absatz 4 BGB excludes the rent increase where it would cause hardship that the landlord's legitimate interests do not justify, looking at the expected future operating costs as well. The exclusion does not apply if the flat was only brought to a customary condition or the work was required by circumstances the landlord is not responsible for. You must raise hardship in writing by the end of the month after the announcement reached you, unless the landlord left out the information about form and deadline. That deadline does not apply if the actual increase exceeds the announced one by more than 10 percent.
I live in a milieu-protection area. Does that help me?
It can. In the areas the city lists, including Nordend-Mitte, Nordend-Süd, Bockenheim, the Berger Straße area, Sachsenhausen-Nord and the western Ostend, building changes need an approval under the preservation statute, even for works that would not otherwise need a permit. Before approving a modernisation, the city's Stabsstelle Mieterschutz writes to the affected tenants and lets them comment. Check your address on planAS (planas.frankfurt.de). The approval does not decide the rent increase, which still follows §§ 559 and following.
Who decides if we disagree about the increase?
The Amtsgericht in whose district the flat lies. [§ 29a ZPO](https://www.gesetze-im-internet.de/zpo/__29a.html) gives rental disputes about premises to that court exclusively (with exceptions for some special kinds of housing), so for a Frankfurt flat it is the Amtsgericht Frankfurt am Main, whose civil divisions sit in the Außenstelle Niederrad, Hahnstraße 25, according to the [court's page](https://ordentliche-gerichtsbarkeit.hessen.de/landgerichtsbezirk-frankfurt-am-main/amtsgericht-frankfurt-am-main). Before going there, use the free city advice or a tenants' association, and keep every letter and the envelope with the date.