Back in 2019 around 3,000 people formed a human chain on the northwestern outskirts of Frankfurt. They were protesting against plans to build a completely new district there that would extend to the borders of the neighbouring Hochtaunus municipalities.

Fast forward to the present. The population of the metropolis on the Main grew by 6,700 in 2024 alone. 776,843 residents were living in Frankfurt at the end of last year – and they not only need a registration certificate, but above all a flat. Preferably affordable. That is quite a challenge in Hesse's largest metropolis, as in so many major German cities.

The situation on Frankfurt's housing market is so precarious that, since the beginning of the year, the housing office has been running a pilot project to check adverts to see whether the rents being charged are within the legal limits. Unsurprisingly, the city's researchers found what they were looking for in the first random sample: They cite evidence of unlawfully high rents in more than 40% of the adverts examined. The landlords are now receiving a letter from the authorities – initially as a friendly reminder of the permissible framework for rentals. However, the city does also have legal tools at its disposal to prevent unreasonable rent increases, in extreme cases.

Only by legal means will the city administration be able to get to grips with a second phenomenon that further weakens the tight housing market: Vacancies. According to estimates, around 11,000 flats are vacant in Frankfurt, many of them due to lengthy renovation work. However, some are left vacant simply for speculative reasons. Legislative processes and court proceedings to counteract these developments are complex and time-consuming.

The city has pressed ahead with its plans for new neighbourhoods in recent years. Only additional living space can alleviate bottlenecks in the property market in the long term. Last week, Frankfurt's neighbouring municipalities, represented by the South Hesse Regional Assembly, approved an expansion of the metropolis. The plans for a northwestern urban quarter can now go ahead, albeit on a somewhat slimmed-down scale compared to the ideas presented over the past decade.

Around 7,000 apartments could be built to the east of the A5 motorway. However, this will not happen quickly either. Those involved estimate that it will take around 15 to 20 years to complete the new district. If Frankfurt continues to grow as fast as it did in 2024, the northwest expansion would be a drop in the ocean.