If we're going to go by these types of correlations, let's add another market with rent control, San Francisco, and you have the two most expensive rental markets in the U.S. Amsterdam, Paris, and Berlin are the top 3 out of 4 on this list of cities with the fastest growing rent prices in Europe: https://www.businessinsider.com/the-7-european-cities-where-.... It seems that a stringent rent control law was only imposed in Barcelona this year.