Lorena Jonas has spent the past eight years fighting landlord rent rises in her trendy Berlin district. Her latest battle, though, could affect not just her neighbours, but hundreds of thousands of tenants across the city.

Jonas is involved in a radical campaign urging Berlin’s city government to expropriate some 240,000 properties from Germany’s biggest publicly listed residential landlords, accusing them of squeezing out lower income, long-term residents through shoddy maintenance and jacked-up rents.

After collecting more than 350,000 petition signatures, their proposal — which targets corporate landlords with more than 3,000 apartments each — will be voted on in a local referendum in September. Polling suggests nearly half of Berliners support expropriation, which would force the companies to sell their properties to the city government at a “fair” price.