Claiming Rent Reductions When Guide Rates Fall

I heard that in Switzerland you can ask your landlord to lower your rent when interest rates go down. Is that right?

Technically, rents are supposed to follow the guide interest rates. You can find these here on the website of the Swiss homeowners’ association:
https://www.hev-schweiz.ch/vermieten/mietverhaeltnis/referenzzinssatz/

As you can see on that page, the guide rate for 2020 is 1.25%. That's 0.25% lower than the guide rate for 2019 (1.5%). That means rents should go down by 0.25%.

For perspective, that is a 60-franc annual saving on a home with a 2000-franc monthly rent. So not a whole lot of money. But if you haven't claimed reductions in many years, the difference can be much higher. For example, in September 2008 the guide rate was 3.5%, or more than double the 2020 rate.

In actual practice, the terms and conditions of your contract may be different. For example, contracts may state that rents are linked to the consumer price index. If you agree to the terms when you sign your rental agreement, then claiming rent reductions may be difficult.

Landlords also have the right to adjust rents in keeping with inflation, and that detracts from rent reductions.