BerlinThe next phase of Berlin's rent cap law is about it kick in. Under the law, existing rents that are more than 20 per cent above the cap will have to be reduced starting 23 November.

The Berlin renters' association (Berliner Mieterverein) has created an English version of its rent cap calculator (embedded below). Answer a few simple questions about your housing situation and you can find out instantly whether you're paying rent above the legally permitted level.

Tenants who find out they are paying excessive rent should contact their landlords or the city's department for urban development and housing, or by using using this online form. The government's information in English is very patchy, so best get a German-speaker to help out.

Rents for around 1.5 million flats have been frozen since 23 February at the level of June 2019 as part of Berlin's unique rent cap and can increase by a maximum of 1.3 percent annually beginning in 2022. Next Monday, 23 November, excessive rents will become illegal. This applies if a rental price is more than 20 per cent above the ceilings set by the state, which have already been applied to new rentals since February.

We've embedded the calculator here to make it even easier for you!

The rent ceilings are calculated according to furnishings, the year of construction, modernisation measures and the location of the flat. Housing minister Sebastian Scheel (Linke) estimates that excessive rents are being charged for about 340,000 apartments.

"If a landlord does not act on their own, the administration will enforce the tenant's claims," the politician said.

Germany's Constitutional Court is expected to decide on the constitutionality of the Berlin's one-of-a-kind rent cap in the second quarter of next year. Until then, Scheel recommends tenants put the rent they save via the reduction aside.