Overview of the Study
The study “Befristet, möbliert und teuer – Geschäftsmodelle am ‚Grauen Wohnungsmarkt‘” was prepared for the Berliner Mieterverein e.V. by Dr. Armin Hentschel of the Institute for Social Urban Development (IFSS) in Berlin‑Potsdam. It investigates the rise of short‑term and furnished rentals in Berlin, examining their scale, drivers, and regulatory environment.
Scope and Methodology
The research focuses on Berlin as a case study but places its findings in a broader German and European context. Data were extracted verbatim from the PDF and supplemented with statistics from the Institute for Housing and Urban Development (IBB), the Federal Statistical Office, and industry reports. The study combines quantitative analysis of housing stock, new construction, and migration flows with qualitative insights from interviews and literature reviews.
Key Market Figures
- Between 2014 and 2023 Berlin added roughly 150 000 new apartments, a 7.3 % increase in housing stock versus a 9 % population growth.
- Annual new construction accounts for about 85 000 housing moves, while the estimated turnover (fluctuation) rate is 5 %, generating roughly 84 000 new tenancy agreements each year.
- Approximately 14 % of Berlin’s 2022 rental market is occupied by short‑term or furnished rentals, with around 18 % of all new tenancy contracts involving such units.
- The median rent for furnished listings is about 24.44 €/m², compared with 11.54 €/m² for unfurnished market rents.
- In 2022, 52 % of all rental advertisements on major portals were for furnished apartments, and 75 % of these listings fell below 7.53 €/m² when calculated as net cold rent.
Drivers of the “Grey” Housing Sector
The study identifies several factors fueling the sector:
- Insufficient new‑build supply and high prices of newly built units.
- Growing demand for flexible, short‑term housing from students, migrants, and mobile workers.
- Profit incentives for landlords and service platforms, especially in inner‑city districts where rents are highest.
- Legal loopholes that allow landlords to bypass rent control and tenant protection through “temporary use” contracts.
Regulatory Landscape
- Berlin’s purpose‑misuse prohibition (Zweckentfremdungsverbot) requires registration numbers for private short‑term rentals, with a €100 administrative fee and a 14‑day processing time.
- Commercial platforms are largely exempt from this registration, creating an enforcement gap.
- The Bezirksämter face staffing shortages (≈ 7.8‑11 full‑time equivalents) and limited technical capacity for data‑scraping, hampering systematic detection of illegal rentals.
- Recent EU regulation (EU 2024/1028) will mandate uniform registration of all short‑term accommodation providers, including detailed unit data, to improve cross‑border oversight.
Economic Impact
Tourism contributes roughly 12.3 billion € to Berlin’s economy, representing 4.3 % of the city’s gross value added and supporting about 250 000 jobs. However, the conversion of residential units to short‑term rentals raises concerns about housing affordability and long‑term availability for residents.
Findings on Data Gaps and Enforcement
The audit by Berlin’s state accounting office revealed at least 2 321 identified illegal short‑term rentals (2018‑2022) versus only 336 units that were re‑registered for residential use. The lack of systematic data‑scraping and limited cooperation from platform operators were cited as major obstacles.
Implications for Sustainable Housing
The study concludes that while short‑term rentals generate economic benefits, they also exacerbate housing shortages and price pressures, challenging the sustainability of urban housing markets. Effective regulation, better data sharing, and coordinated European standards are recommended to balance tourism income with the need for affordable, long‑term housing.

