Paris's Duplicate Image Problem: The Key Decisions That Will Shape the City's Visual Archive

Thousands of duplicate images are clogging the digital archives of Paris's public institutions, and the people responsible for managing them are running out of time to act. The problem has been building for years across agencies involved in the Grand Paris Express construction project, the Paris 2024 Olympic legacy documentation programme, and the Seine riverfront regeneration initiative — but it has reached a point where decisions can no longer be deferred.

The issue matters now because several of these institutions face contractual deadlines tied to Phase 2 of the Grand Paris Express rollout, with new stations along Line 15 South scheduled to open before the end of 2026. Documentation archives underpinning environmental impact assessments and public communication materials must be cleaned, catalogued, and certified before those openings. A bloated image library doesn't just slow down archivists — it creates legal and administrative exposure when the wrong version of a document image ends up in a public planning file.

Where the Backlog Is Worst

The pressure is most acute at two institutions. The Atelier Parisien d'Urbanisme, known as APUR, maintains a visual record of planning and development stretching back decades; staff there have flagged internally that duplicate capture from drone surveys of the Plaine Saint-Denis redevelopment zone has produced overlapping image sets that have never been reconciled. Separately, the Bibliothèque nationale de France's digital preservation unit on the Quai François-Mauriac in the 13th arrondissement is contending with redundant scans from heritage digitisation runs conducted between 2022 and 2024 — many of which were uploaded multiple times as different teams worked on the same source material without a shared deduplication protocol.

The practical consequences are tangible. Storage costs for unresolved duplicates in public cloud infrastructure have increased substantially across French municipal bodies in recent years, according to reporting by French technology press outlets, with some estimates suggesting duplicates account for between 20 and 35 percent of total image storage in poorly managed public archives. For Paris, where the municipal budget already faces scrutiny from a National Assembly increasingly focused on public spending efficiency, that is not a number administrators want on the record.

The Decisions That Cannot Wait

Three choices will define what happens next. The first is whether to pursue manual deduplication — expensive, slow, but legally defensible — or deploy one of the emerging AI-assisted tools that can identify near-duplicate images using perceptual hashing and metadata comparison. Several French tech firms, including some operating out of the Station F campus near the Bibliothèque nationale, have pitched versions of these tools to public clients, but procurement under French administrative law requires a formal tender process that adds months to any timeline.

The second decision concerns governance: who owns the deduplication standard. Right now, APUR, the Direction de l'Urbanisme at the Hôtel de Ville, and the cultural institutions along the Seine operate under different archiving protocols with no unified authority. A joint working group involving all three was proposed in early 2025 but has not formally convened. Whether the Mairie de Paris moves to formalise that coordination — or leaves each body to solve the problem independently — will determine whether any solution scales or simply shifts the bottleneck.

The third question is timeline. The Line 15 South certification requirement creates a hard external deadline, but the Seine regeneration project's communications archive — centred on work between the Pont de Bercy and the Pont de Tolbiac in the 13th arrondissement — has no equivalent forcing function. Without one, experience from similar projects in other European capitals suggests the archive simply grows messier as new material is added on top of unresolved older layers.

Staff at the affected institutions will know more after a planned inter-agency meeting at the Hôtel de Ville, expected before the August recess. What comes out of that meeting — a procurement mandate, a governance framework, or another deferral — will determine whether Paris enters the autumn with a credible plan or a larger problem than the one it started with.