BERLIN (AP) — Low-cost housing advocates are launching a grassroots campaign to force Berlin's state government into taking over nearly 250,000 apartments worth billions from corporate owners to fight rising rents in one of Germany's hottest real estate markets.

The fight pits two philosophies against one another: free-market companies that see real estate as a means to profit, and housing activists who see affordable rent not only as a necessity but as central Berlin's character. Its prospects are uncertain at this early stage and a resolution will take years.

The city had been a low-rent mecca after the fall of the Berlin Wall in 1989 opened the gates to the economically depressed former communist east of the city. That gave rise to an influx of artists and others seeking a more bohemian existence.