The Barcelona court justified its decision in a ruling dated November 29 which was released by the home rentals website on Monday on the grounds that there is a legal vacuum regarding the regulation of the "sharing economy" in Spain.

"The regulation of this new phenomenon of consumption has been left orphaned... and this can't be substituted by imposing a fine," the court said in its ruling after hearing Airbnb's appeal.

It is the first time that a fine against Airbnb has been overturned by a Spanish court.

Catalonia, home to the seaside city of Barcelona, slapped Airbnb with the fine in July 2014 for breaching local laws requiring any flat or house rented to tourists to be registered with the region's tourism authority. The region tightened its rules on hospitality in 2012, saying this was needed to better control the quality of services on offer.

San Francisco-based Airbnb welcomed the court ruling, saying it was "key" to solving its legal issues in Catalonia.

"Airbnb is part of the solution in Barcelona and we want to work with leaders on clear, fair rules for home sharing. We hope this ruling will kickstart a new conversation on how we can work together," it said in a statement.

Barcelona city hall, led by a former anti-evictions activist, last month fined Airbnb and its rival HomeAway 600,000 euros ($635,000) each for marketing lodgings that lacked proper tourist permits.

Airbnb, which lets homeowners share their homes for a fee by marketing them online, has become a popular alternative to hotels and mirrors consumers' growing reliance on online sharing services in other areas such as transport, including cars.

Catalonia has figured prominently in its growth, with Barcelona consistently ranking as one of the site's largest markets. But the company has recently faced mounting criticism from some quarters that it exacerbates housing shortages and squeezes the long-term rental sector. At the same time, several cities are exasperated by what is regarded as a service which appears to lack the legal and tax constraints of commercial enterprises.

New York, Miami and Berlin are just some of the other cities that have cracked down.

is/cho (afp)