In 2020, the City of Barcelona introduced a new rent-setting system based on the concept of a reference rent. Rents of contracts entered into after 1995 must be lowered if they are above the reference rent level. The new law also covers non-rent service charges but does not cover dwellings built in the last three years, or social housing.
There are fines for non-compliance, ranging from EUR 3,000 to EUR 90,000 depending on the seriousness of the offence. The new law applies to 61 municipalities in Barcelona.
 For a practical guide to the Rental Price Regulation Law, see https://habitatge.barcelona/en/noticia/everything-you-need-to-know-about-the-rental-price-regulation-law_1037623.