Your Berlin Rental Building Got Sold as Condos: The 10-Year Protection, and Why Milieuschutz Changes the Odds

The Official Rule

Getting word that your building has been sold and carved up into individually owned apartments is unsettling, but the sale by itself doesn’t put your tenancy at risk. What actually matters is the rule that kicks in once your own specific unit is sold on to a new individual owner, and in Berlin that rule sits underneath a much thicker stack of permission requirements than almost anywhere else in Germany.

Once your unit is sold to a new owner after the building has been converted into condominiums, that owner cannot terminate your tenancy for Eigenbedarf or economic exploitation for 10 years, not the 3-year federal baseline. Section 577a BGB sets the nationwide floor at 3 years but lets state governments extend it to as much as 10 years in areas with a genuinely tight rental market. Berlin has used that authority citywide, in all 12 districts without exception, since October 1, 2013, under its own Kündigungsschutzklausel-Verordnung. Two earlier versions of the ordinance, from 2004 and 2011, only protected tenants for 7 years and only in 4 to 6 districts. The 2013 version extended both the length and the coverage to the entire city in one step, the Senate renewed it again on June 13, 2023, and the Bundesgerichtshof confirmed the ordinance’s validity in a June 2022 ruling (VIII ZR 356/20), finding the state legislature had acted well within its discretion.

What makes Berlin genuinely different from Munich’s version of this protection is not the number of years, it’s everything that has to happen before that number ever starts counting. Munich’s extended protection depends on Bavaria checking whether a municipality made a state list of housing-strained areas. Berlin instead makes actually converting a rental building into sellable condominium units difficult in the first place, through two separate and overlapping permission regimes.

The first regime applies to the entire city. Since January 1, 2026, a renewed Umwandlungsverordnung under Section 250 BauGB, decided by the Senate on November 11, 2025, requires official Land permission before any existing rental building with more than 5 apartments can be split into individual condominium ownership anywhere in Berlin. The ordinance runs through December 31, 2030. Its earlier version, in force since 2021, already had a dramatic effect: citywide conversions fell from 28,783 apartments in 2021 to just 1,552 in 2024. Permission still has to be granted in a handful of situations, inheritance among heirs, sale to family members for their own use, or sale to at least two-thirds of the sitting tenants for their own use, but outside those, the Land can simply refuse it.

The second regime is older, narrower in geography, and stricter in substance, and it’s the one most people actually mean by “Milieuschutz.” More than 80 soziale Erhaltungsgebiete, social preservation areas designated under Section 172 BauGB, now cover parts of 10 of Berlin’s 12 districts, with Mitte and Pankow each holding around 14 of them. Inside these zones, converting a rental building into condominiums needs district permission no matter how small the building is, and permission is generally denied outright to protect the existing social composition of the neighborhood. The main way an owner still gets approval is Section 172 Abs. 4 Satz 3 Nr. 6: committing in writing to sell the new units only to sitting tenants for 7 years after the conversion is registered.

What Real People Say

Tenant guides and Mieterverein caseworkers are candid that Milieuschutz alone has a mixed track record of actually stopping conversions. A widely cited Mieterecho analysis by the Berliner MieterGemeinschaft found that between 2015 and 2017, districts approved 5,849 conversions under the very exceptions built into Section 172, while only about 15 apartments across the whole city were actually sold to sitting tenants under the right-of-first-refusal that’s supposed to be the main defense. Of Berlin’s districts, only Friedrichshain-Kreuzberg consistently exercised its Vorkaufsrecht at all during that period, in 22 cases. That gap between the rule on paper and what happened on the ground is exactly why practical guides tell tenants not to treat “my building is in a Milieuschutzgebiet” as protection on its own.

The practical advice circulating through tenant-support resources like Baustelle Gemeinwohl comes down to three checks, run in this order. First, confirm your address actually sits inside a designated Erhaltungsgebiet using the Senate’s own Geoportal, not just a rumor about your Kiez. Second, contact your district’s Stadtentwicklungsamt to find out whether, and when, your specific building actually received an Umwandlungsgenehmigung, since the permission date matters as much as the sale date for working out which protections stack. Third, if a termination notice does arrive, get the exact Grundbuch registration date for the new owner before assuming anything about timing. Guides describing longer-settled tenants in Milieuschutzgebiete sometimes talk about “7 plus 5” years of combined protection, the 7-year tenant-sale commitment under Section 172 layered with whatever remains of other safeguards, though caseworkers are quick to note the exact stacking depends on your building’s own history and is worth a real consultation, not a rule of thumb.

The April 2026 change to furnished short-term rentals inside Milieuschutzgebiete is a related but separate story. As furnished, time-limited listings grew from about 13 percent of Berlin’s rental listings in 2012 to roughly 48 percent by 2025, with asking prices on those listings running well above ordinary leases, districts started seeing them used as a way to sidestep standard tenancy protections entirely, without ever going through a formal Eigenbedarf termination. Since April 18, 2026, offering a furnished apartment in any of Berlin’s Milieuschutzgebiete on a time-limited basis needs district permission too, under new administrative guidance that followed an April 2025 Verwaltungsgericht Berlin ruling. It doesn’t change the 10-year Umwandlungsschutz itself, but it closes a workaround that had been growing right alongside it.

Step by Step

1. Check whether your building sits inside one of Berlin’s more than 80 Milieuschutzgebiete, using the Senate’s Geoportal or your district’s Stadtentwicklungsamt, since that changes which permission rules applied before any conversion could happen at all.
2. If you’ve been told the building was converted, ask the district when the Umwandlungsgenehmigung was actually granted, and under which exception, since a Section 172 tenant-sale commitment works differently from a straightforward Section 250 approval.
3. If your specific unit is sold, get the exact date the new owner was entered in the Grundbuch, not the date of the sale contract, since that registration date is what starts the 10-year clock under the Kündigungsschutzklausel-Verordnung.
4. If a termination notice for Eigenbedarf or economic exploitation arrives, calculate whether 10 full years have passed since that registration date, since Berlin’s citywide protection runs through at least 2033 regardless of district.
5. Don’t assume Milieuschutz alone protects you, given how few conversions it actually blocked historically, and get a second opinion from the Berliner Mieterverein or the Berliner MieterGemeinschaft if a notice looks premature.
6. If you’re offered a furnished, time-limited lease instead of a normal one inside a Milieuschutzgebiet after April 2026, ask whether the landlord actually holds the district permission now required for that.

Compliance Note

This page explains the general framework around Section 577a BGB, Berlin’s Kündigungsschutzklausel-Verordnung, and the Section 172 and Section 250 BauGB permission regimes as they apply in Berlin in mid-2026. It is not legal advice, and whether a specific termination or conversion is valid depends on your building’s own permission history, your move-in date, and the exact Grundbuch registration date of any new owner. Confirm your own situation with a Mieterverein, the Berliner MieterGemeinschaft, or a tenancy lawyer before assuming a particular notice is valid or invalid.