How Barcelona's Housing Rental Database Got Buried Under Duplicate Listings — And What's Being Done About It

Barcelona's short-term rental crackdown has a data problem. The city's unified rental registry, which Ajuntament de Barcelona began consolidating in earnest after the 2021 revision of the city's tourist apartment ordinance, has been quietly undermined by thousands of duplicate property images spread across overlapping municipal databases — making it harder for inspectors to match unlicensed flats to their owners and slowing enforcement in neighbourhoods where the housing crisis bites hardest.

The timing matters. Mayor Jaume Collboni has staked significant political capital on reining in the short-term rental sector, pledging not to renew any of the roughly 10,000 tourist apartment licences when they expire by November 2028. The credibility of that promise depends entirely on the city's ability to prove, flat by flat, which properties are operating legally — and duplicate image records make that job measurably harder.

A Registry Built on Layered Mistakes

The roots of the problem stretch back to at least 2016, when the city launched the HUT (habitatges d'ús turístic) registration system under then-mayor Ada Colau's administration. Operators submitted photos of their properties as part of licence applications, but the images were stored in at least three separate departmental systems: the Oficina d'Habitatge, the Departament de Llicències i Inspecció, and a parallel feed from the Registre de Turisme de Catalunya managed at regional level by the Generalitat. None of the three systems talked to each other automatically.

When the city moved to centralise records under the Pla pel Dret a l'Habitatge 2016–2025, technicians migrating data pulled images from all three sources without running deduplication checks first. A single flat in Gràcia or the Eixample could appear with four or five separate photo sets, each tied to a slightly different property identifier. Inspectors working the Barceloneta waterfront and the Raval — two of the most enforcement-heavy zones in the city — reported wasting significant time cross-referencing images that should have been collapsed into a single record.

The city does not publish a precise count of affected listings, but housing advocacy group Sindicat de Llogateres has argued publicly, in documented submissions to the Ajuntament, that data quality failures across the registry have contributed to enforcement gaps. Airbnb listings in Barcelona numbered around 16,000 active properties as recently as late 2024, according to data aggregator AirDNA, despite the formal licence cap sitting well below that figure.

What the Fix Actually Requires

Deduplicating image records is not a trivial technical task. Property photos submitted years apart may have different resolutions, different EXIF metadata, and different filenames even when they show the same kitchen on Carrer del Consell de Cent. Standard hash-based matching fails in those cases. The city's IT contractors have reportedly been trialling perceptual hashing — a technique that compares visual fingerprints rather than raw file data — but integrating that into a live administrative database requires sign-off from both municipal and Generalitat systems teams, adding a layer of intergovernmental friction that has slowed progress.

Barcelona is not alone in facing this. Lisbon's Alojamento Local registry ran into similar problems after Portugal's 2023 Mais Habitação law triggered a rush of new licence applications and data migrations. The difference is that Barcelona's enforcement calendar is fixed: the November 2028 licence expiry is a hard deadline, and the image-deduplication work needs to be complete well before then to give inspectors usable data.

For landlords and operators, the practical advice is straightforward. Anyone with an active HUT licence should log into the Seu Electrònica of the Ajuntament and verify that their property record carries a single, consistent set of images tied to their NIE or CIF. Discrepancies — multiple entries, mismatched addresses, orphaned photos — should be flagged to the Oficina d'Habitatge at Carrer de Llull 161 before the city's own audit process flags them instead. Records flagged by the city's system, rather than corrected proactively by operators, are likely to face longer resolution times and potential suspension of licence status during review.

The city has not announced a public-facing tool for operators to check their own duplicate status, but housing officials have indicated that a registry transparency portal is planned for the first quarter of 2027.