Barcelona authorities says they will fine vacation rental websites Airbnb and HomeAway 600,000 euros ($633,000) each for offering lodging that doesn’t have the necessary permits, in the latest move to curb mass tourism in the Spanish city.

Barcelona Mayor Ada Colau told Catalunya Radio that while tourism was a positive asset for the city, it had grown too much and was denying locals access to housing.

City Hall said the two companies had been found to be continuing to offer unlicensed accommodation despite having been fined smaller amounts earlier this year for the offense.

Colau, a former anti-eviction group activist, promised to curb excess tourism in the city following complaints from residents.