Airbnb said it was saddened by the decision and would appeal. “Barcelona is the only city in the world to have fined us,” noted Airbnb in a statement on its website, adding: “Barcelona is going in the opposite direction to the majority of cities in Europe and the world, and unlike those cities, has shown no real interest in exploring a constructive dialogue with Airbnb in recent months.”

“Less than a month ago we met with officials and Airbnb committed to work together in the best interests of the city. Airbnb is part of the solution in Barcelona,” the Catalan division of Airbnb said in the statement released on Thursday.

It is not the first time the city has fined San Francisco-based Airbnb, one of the fastest-growing start-ups of the so-called sharing economy valued at around $25 billion.

Barcelona City Hall reported that Airbnb and Homeaway were repeat offenders, and were both fined €30,000 in August for failing to follow regional tourism laws. Homeaway paid the fine, while Airbnb appealed against it but both continued to publicize unlicensed apartments said left-wing Mayor Ada Colau justifying her decision to impose the new €600,000 fines.