Berlin’s 2026 rent index is up 6.9% versus 2024. What §558 BGB and the rent brake (extended to 31 Dec 2029) allow on re‑letting in Berlin and Frankfurt this year—and the key exceptions.
Berlin released its 2026 qualified Mietspiegel on 28 May 2026. The Berlin Tenants’ Association reports an average local reference rent (ortsübliche Vergleichsmiete) of €7.71/m², up 6.9% from €7.21/m² in the 2024 index. Berlin confirms the 2026 table structure, methodology and qualified status in the official brochure. The underlying reference date for rents is 1 September 2025, as shown in the tables. ([berlin.de](https://www.berlin.de/sen/stadt/presse/pressemeldungen/pressemitteilung.1674998.php?utm_source=openai))
Frankfurt am Main recognized and published its 2026 qualified Mietspiegel on 25 June 2026. The city states that the 2026 rent index is qualified under §558d BGB and that the 2024 index applied as a simple index in the short transition until 24 June 2026. The 2026 brochure sets out validity until 31 May 2028 and provides the calculation method, including a base net rent by size and surcharges for features and location. ([frankfurt.de](https://frankfurt.de/themen/planen-bauen-und-wohnen/wohnen/informationen-zum-wohnungsmarkt/mietspiegel))
For investors, the practical impact is twofold: for existing tenancies, §558 BGB limits rent increases to the local reference rent evidenced by these Mietspiegel; for new lettings, the rent brake (Mietpreisbremse) caps the initial rent relative to the local reference rent where a state regulation designates a tight market. We summarize both below. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__558.html?utm_source=openai))
Germany’s rent brake is anchored in §§556d–556g BGB. In areas designated by state ordinance as “tight housing markets,” the initial rent at re‑letting may be no more than 10% above the local reference rent (§556d(1) BGB). The federal legislature extended the legal basis to 31 December 2029 in 2025 (BGBl. I 2025 Nr. 163). ([gesetze-im-internet.juris.de](https://www.gesetze-im-internet.juris.de/bgb/__556d.html?utm_source=openai))
Designation on the ground: - Berlin applies the brake city‑wide. The Senate confirms the extension of the Berlin ordinance (“Mietenbegrenzungsverordnung”) so that the brake continues to apply in the entire city; on 19 September 2026 Berlin announced the rent brake now runs to end‑2029. ([berlin.de](https://www.berlin.de/aktuelles/10014766-958090-mietpreisbremse-bis-2029-verlaengert.html)) - Frankfurt applies the brake under the Hessian Mieterschutzverordnung, which the city’s guidance cites for “max. +10%” at re‑letting across the city. ([frankfurt.de](https://frankfurt.de/themen/planen-bauen-und-wohnen/wohnen/informationen-zum-wohnungsmarkt/mietspiegel))
Statutory exceptions are narrow and must be disclosed to the tenant in writing (§556g BGB): - New build: dwellings first used and let after 1 October 2014 are exempt. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__556f.html)) - First letting after “comprehensive modernization” (umfassende Modernisierung) is exempt. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__556f.html)) - Prior rent (Vormiete): if the previous lawful rent exceeded the brake cap, the landlord may charge that prior rent to the new tenant, subject to disclosure duties. Modernization completed within the last three years before contract start can also justify an amount above the cap, by reference to §559 BGB calculations. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__556e.html?utm_source=openai))
Risk if you overcharge: a tenant can object (Rüge). If the objection comes more than 30 months after the tenancy began or after it has ended, only future rent can be reclaimed; earlier recovery requires a timely objection. Investors should ensure files contain the written disclosures required by §556g BGB. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__556g.html?utm_source=openai))
Illustration using the official tables: - Berlin (mittlere Wohnlage): for a 55–60 m² flat built 1986–1990 (West), the 2026 table shows a Mittelwert of €9.97/m². The headline brake cap at re‑letting is therefore €10.97/m² (9.97 × 1.10), unless a statutory exception applies and is properly documented. ([mietspiegel.berlin.de](https://mietspiegel.berlin.de/wp-content/uploads/2026/05/mietspiegel2026.pdf)) - Frankfurt: the 2026 brochure lists a base net rent of €9.02/m² at 70 m² before feature and location surcharges. Absent surcharges, the +10% brake cap would be €9.92/m² (9.02 × 1.10). Always perform the full Frankfurt calculation (base by size, then permitted surcharges, then compare to the brake cap). ([frankfurt.de](https://frankfurt.de/-/media/frankfurtde/service-und-rathaus/verwaltung/aemter-und-institutionen/amt-fuer-wohnungswesen/pdf/64_s1/64_s1_frankfurter_mietspiegel_2026.pdf?dmc=1))
For existing contracts, §558 BGB permits increases up to the local reference rent, subject to form and timing rules. The “Kappungsgrenze” caps net‑cold rent increases (excluding modernization and operating‑cost adjustments) at a maximum of 20% over three years nationwide, reducible by state ordinance to 15% in stressed markets. Both Berlin and Frankfurt currently apply the 15% cap. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__558.html?utm_source=openai))
- Berlin: the state confirms a 15% cap within three years in its housing policy pages. The qualified Berlin Mietspiegel 2026 must be referenced in formal increase notices when applicable. ([berlin.de](https://www.berlin.de/sen/wohnen/wohnungs-und-mietenpolitik/?utm_source=openai)) - Frankfurt: the city states a 15% three‑year cap via the Hessian Mieterschutzverordnung, with additional local guidance on form requirements. ([frankfurt.de](https://frankfurt.de/themen/planen-bauen-und-wohnen/wohnen/informationen-zum-wohnungsmarkt/mietspiegel))
Note that modernization surcharges are governed by §§559–559a BGB, not by §558, and that index‑linked and graduated rents have special rules (§§557a–557b BGB). Initial rents under index agreements are still subject to the rent brake where designated. Investors should have German counsel review any planned increase or new lease wording before issuance. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/BJNR001950896.html?utm_source=openai))
Berlin: identify the building’s completion period, the dwelling size band, and the location class (simple, medium, good). The 2026 brochure explains how to position within the range using feature groups; the Mittelwert is the starting point for typical standard quality. Use the 2026 tables with the 1 September 2025 reference date. ([mietspiegel.berlin.de](https://mietspiegel.berlin.de/wp-content/uploads/2026/05/mietspiegel2026.pdf))
Frankfurt: start with the base net rent by exact square metre (Table 1), then apply only the listed surcharges/discounts for qualifying features and the location factor as directed in the brochure. The city provides an online calculator for 2026 and publishes the documentation and the location directory. ([frankfurt.de](https://frankfurt.de/-/media/frankfurtde/service-und-rathaus/verwaltung/aemter-und-institutionen/amt-fuer-wohnungswesen/pdf/64_s1/64_s1_frankfurter_mietspiegel_2026.pdf?dmc=1))
Always compare your computed rent against the applicable legal ceiling: for re‑letting, the rent brake cap (+10% above local reference rent) if the brake applies; for existing tenancies, the lowest of (i) the computed local reference rent and (ii) the 15% three‑year cap where in force. Keep written records of any exception relied upon and the disclosures provided under §556g BGB. ([gesetze-im-internet.juris.de](https://www.gesetze-im-internet.juris.de/bgb/__556d.html?utm_source=openai))
- Berlin announced on 19 September 2026 that its rent brake continues city‑wide through 31 December 2029. For suspected overpricing at re‑letting, Berlin’s Mietpreisprüfstelle is the official contact; the Senate also conducts market scans using the 2026 Mietspiegel. Landlords should expect active scrutiny. ([berlin.de](https://www.berlin.de/aktuelles/10014766-958090-mietpreisbremse-bis-2029-verlaengert.html)) - Frankfurt’s housing office publishes guidance and an information sheet on the rent brake and on excessive pricing; the 2026 rent index page links to both. ([frankfurt.de](https://frankfurt.de/themen/planen-bauen-und-wohnen/wohnen/informationen-zum-wohnungsmarkt/mietspiegel)) - Seek advice from a German real‑estate lawyer on whether an exception (new build, comprehensive modernization, prior rent) truly applies and on the exact disclosure wording under §556g BGB. This article is not legal advice. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/bgb/__556f.html))
Nothing on this page is investment, tax or legal advice. Price bands are indicative asking prices and disagree between sources by design. Verify every figure with a qualified German notary, tax adviser (Steuerberater) or lawyer before committing capital.
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