Barcelona's Housing Platforms Move to Fix Duplicate Listing Problem That's Been Inflating Rental Counts

Barcelona's municipal housing authority confirmed this week that it is accelerating a systematic audit of short-term rental platforms operating in the city, with duplicate image detection at the centre of the effort. Properties appearing under multiple listings with identical or near-identical photographs have been skewing official counts of active tourist apartments — a distortion that has complicated enforcement of the city's rental crackdown since Mayor Jaume Collboni began tightening restrictions in 2024.

The problem matters now because the city is in the final stages of allowing roughly 10,100 existing tourist apartment licences to lapse without renewal — a policy set to conclude by November 2028 that the Ajuntament de Barcelona has described as a decisive step toward returning housing to long-term residents. If the underlying data used to track compliance is polluted by duplicate listings, inspectors working out of the Oficina de l'Habitatge cannot accurately measure how many apartments have genuinely exited the short-term market.

How Duplicate Images Distort the Count

The mechanics are straightforward. A single apartment in, say, the Eixample or Gràcia can appear simultaneously on Airbnb, Booking.com and a local platform such as Apartur-affiliated agencies, each listing carrying the same bedroom photographs. Automated scraping tools used by the city's housing directorate would register these as three separate properties. Multiply that across thousands of units and the active inventory figure inflates significantly — making the rental market look larger, and enforcement gaps look smaller, than they actually are.

Duplicate image replacement — the process of flagging, removing or consolidating listings that share photographic fingerprints — has become a technical priority for the Consorci de l'Habitatge de Barcelona, the joint city-Generalitat body that administers housing policy across the metropolitan area. Engineers working with the consorci have been piloting perceptual hashing tools, a form of image comparison technology, to cross-reference listings scraped from major platforms. The pilot began in earnest during the first quarter of 2026, according to documentation published on the consorci's open-data portal.

The scale of the issue is not trivial. An independent study published in March 2026 by the Institut Metropolità de Promoció de Sòl i Gestió Patrimonial estimated that between 12 and 18 percent of active listings in the Sant Pere, Santa Caterina i la Ribera district and the lower stretch of the Passeig de Gràcia corridor could be attributed to duplicate entries rather than distinct physical units. That range, if applied to the city's total registered inventory of around 10,100 licences, suggests that somewhere between 1,200 and 1,800 listings may represent properties already counted elsewhere.

What the Platforms Are Being Asked to Do

Under pressure from City Hall, the major platforms have been handed a deadline of 1 September 2026 to implement their own deduplication protocols and report consolidated unique-unit figures to the Ajuntament. Airbnb and Booking.com have both acknowledged receipt of the requirement through their respective Barcelona market offices, though neither has publicly detailed the technical approach they plan to use.

For residents in places like the Poblenou neighbourhood — where the 22@ innovation district sits alongside streets that have seen aggressive short-term rental expansion — the practical consequence of cleaner data should be faster enforcement action. Inspectors from the city's Agència de l'Habitatge will be able to cross-reference licence numbers against deduplicated listing databases, making it harder for landlords to argue that a flagged property is already accounted for under a different entry.

The tourist tax angle adds further urgency. Barcelona raised its tourist overnight tax to €4 per person per night for apartments in April 2025, and accurate unit counts are directly tied to revenue projections the city uses to fund social housing acquisition. Inflated inventory figures produce inflated projected tax income — a budgetary miscalculation the Ajuntament's housing finance team is keen to correct before the 2027 municipal budget cycle opens in October.

For tenants, landlords and anyone monitoring the housing market, the immediate practical step is to cross-check any rental listing against the Registre de Turisme de Catalunya database, which carries official licence numbers. A property appearing without a valid, searchable licence number — regardless of how many platforms it appears on — should be reported to the Oficina de l'Habitatge at Carrer del Bisbe Caçador 4 in the Barri Gòtic. The September platform deadline will be the first real test of whether the technical fix translates into cleaner numbers on the ground.