New Berlin rent register will use AI to find rent exploitation cases and fine landlords

Members of the Berlin House of Representatives (Abgeordnetenhaus) are set to vote on whether the city should introduce a rent register. What is written in the draft law, and what would it mean for tenants?

Berlin Abgeordnetenhaus vote on rental law

On July 2, members of the Berlin House of Representatives are to vote on a draft law, the “Housing Space Security Law” or “Wohnraumsicherungsgesetz”.

The law has already passed a first reading and has been referred to relevant committees for deliberation. It passed this stage with support from the governing CDU-SPD coalition and the Greens. The Left Party abstained, and the AfD voted against the law.

On Thursday, representatives will vote on each clause of the draft law and on the law as a whole. If it passes this second reading, the law will be promulgated by Mayor Kai Wegner (CDU) within two weeks.

Berlin’s Mietenkataster law explained

So, what is written in the Wohnraumsicherungsgesetz? Under the new law, local government would create a city-wide rent register (Mietenkataster) of 1,75 million flats. After the law takes effect, landlords will have 12 months to enter information about their rental properties into the register.

Landlords would be required to log the following information: 

• Rental address and floor level
• Size of the rental space
• The number of rooms and any furniture
• The name of the landlord and tenant (which would be anonymised)
• The number of occupants
• The issue date of any certificate of eligibility for subsidised housing, if applicable
• Rental contract start date and agreed length
• Rent amount charged before utility bills
• Outline of utility charges: overheads, water bills and heating
• Information on when the flat was last modernised and its current state
• Proportion of property tax

If landlords do not enter the above information into the register within 12 months, they will face fines of up to 10.000 euros. Landlords who fail to provide information on multiple occasions face fines of up to 100.000 euros.

Chairman of the landlord association Haus & Grund, Carsten Brückner, has pointed out that landlords will be able to refuse to provide information relevant to criminal proceedings, according to rbb. However, if a landlord refuses to give information for this reason, authorities will still be able to investigate, for example by going directly to the tenant for information.

AI will check information against rent brake law

The aim of consolidating all of this information is to make it easier for local authorities to spot and act on cases of rent exploitation.

Germany already has a rent brake law, known as the “Mietpreisbremse”, which sets the maximum amount landlords can legally charge tenants. The law applies in areas with a “strained housing market”, where rents are higher than the German average, or where the population is growing quickly despite few new houses being built. 

In an area with a “strained housing market”, landlords cannot charge more than 10 percent over the “local comparative rent”. The local comparative rent is determined by the rent index, known as the “Mietpreisindex” or “Mietspiegel” in German.

This nationwide law was introduced by the CDU in 2015, but it has long been criticised for having many loopholes. Even if tenants suspect they are being charged an illegally high rent, the process of challenging landlords can be risky, opaque and arduous. 

As a result, rent exploitation is widespread. Established in 2025, Berlin’s Rent Price Review Office (Mietpreisprüfstelle) found that landlords were charging tenants illegally high rents in 94 percent of the 340 rental contracts it reviewed that year.

While tenants have to report suspected violations to the Mietpreisprüfstelle, the mandatory rent register should help automate the process by which authorities identify and challenge cases of exploitation.

“If you analyse [the rent register] using AI, you can – regardless of whether a tenant notices it themselves – see whether the rent is likely to be too high,” Housing Senator Christian Gaebler (SPD) told rbb.

The CDU-SPD coalition also hopes that the initial 12-month window during which landlords must register information will encourage them to reduce rents to within legal limits or to do so of their own accord.

If the law is passed on July 2, Berlin would become the first federal state with a centralised, digital rent register.