In 2020, Catalonia (the region of Barcelona) implemented a restrictive rent control mechanism. Defining a price index in the area, depending on the features of the unit, any owner could surpass the limit of it. By doing so, in the year the limit was set in place, the prices decrease compared to other areas without the regulation.

Barcelona, as a global city, faced a big challenge: housing rent. The city has a low social housing stock and private owners had a lot of power to determine the price of the rent. As a result, a speculative increase on the rent was set in place. To avoid it, the government of Catalonia implemented a rent control that became one of the most restrictive ones in Euroe

In 2020, the Catalonia Government created a price index for each area of the country. The price index was based on the features of the building and the rent currently paid in the zone (in new and old contracts). Then, all new contracts made in the zones must be lower than the index. There were fines for non-compliance, ranging from EUR 3,000 to EUR 90,000 depending on the seriousness of the offence.

After a year in motion, the policy was overruled by the constitutional court. The argument was not about the content, but about the legal power Catalonia had to do the regulation. For this reason, in 2024, Catalonia promoted a new rent control based on the legal framework of the Spanish State. In this case, the price index only affects owners of more than 5 housing units. For the rest of landlords, the limitation is that the new contract cannot be above the old one.

Although it is too early to assess the new regulation, the one in 2020 has proved to be effective. Doing a diff-in-diff analysis, the Observatory of Metropolitan Housing (the public agency responsible to assess housing policies) stated that the regulation lowered the price for tenants during the year it was enforced.