In 1901, the City of Paris organised a competition to find the city's best rat catcher. The newspaper Le Figaro reported the outcome: the competition failed. "The rats in Paris learn very quickly how the traps work and manage to skilfully remove the bait without being caught," an article from December 1901 noted. "The Parisian rat is a very special animal, by no means stupid, which has nothing in common with the coarse country rat or the naive provincial rat."

One hundred and twenty-five years later, Paris is still trying.

Paris's rat problem is not a metaphor. It is a municipal emergency with an ideological dimension. The current estimate puts the city's rat population at between 4 and 6 million — two to three rats for every one of Paris's 2.2 million human residents. The population has risen by 50% since 2015. Paris is now ranked fourth globally for rat density per inhabitant. And approximately half of the city's rats are immune to the anticoagulant poison that remains the primary tool of official control — because anticoagulants have been used so heavily, for so long, that the rat population has evolved around them.

The rats have become a defining issue of the 2026 Paris municipal elections. Conservative candidate Rachida Dati has promised a "large-scale plan to combat the rat infestation." Socialist candidate Emmanuel Grégoire has proposed special city police brigades to patrol rat-prone areas. A councillor from the Animal Party appeared at a market with a tame rat named Plume on his shoulder, arguing for cohabitation over extermination.

The ideological dimension is real. A survey found that 61% of Parisians are now opposed to lethal means of rat control. A Paris city-funded study — Project Armageddon, which despite its name is focused on managing coexistence rather than elimination — is asking how humans and rats can share the city in a way that is "most efficient and at the same time not unbearable for Parisians." The city government has pointed out that rat population estimates are unrealistic because no actual count has been conducted. "Such a count is very complex in cities," the city notes.

The DansMaRue app allows Parisians to report rat sightings with photographs. Specialists are deployed approximately 7,000 times a year in response. Parks are periodically closed to allow eradication campaigns. Garbage bins have been retrofitted with hermetic closures.

None of it is working well enough.

The Paris rat problem is, at its core, an innovation problem. The city has tried the available tools and found them insufficient. The rats have out-evolved the poison. The political will for lethal control is declining. The population is growing. And the most promising emerging approaches — rat oral contraceptives, AI-powered burrow detection, real-time population mapping, ultrasonic deterrence, genetic approaches to fertility control — exist in laboratories and pilot programmes in cities around the world, not yet assembled into a deployable system.

What Paris needs is not another eradication campaign. It is the assembled intelligence of every city that has been fighting the same problem from a different angle.

A global urban rat hackathon would not be absurd. It would be the most honest acknowledgement Paris has yet made of the scale of the problem: that the city which invented the competition in 1901 and lost needs to open the competition to the world.

(Sources: The Star / Blue News / Big Think / City Journal / CNN / Fortune / City-Paris.fr — 2022–2026)

New York 🇺🇸 — New York has been fighting rats longer than Paris and with more money. Mayor Eric Adams launched a high-profile rat czar initiative in 2023 — appointing Kathleen Corradi as the city's first Director of Rodent Mitigation. The programme introduced dry ice carbon dioxide injection into rat burrows, new compactor garbage trucks to deny access to food sources, and data-driven targeting of interventions based on 311 complaint density mapping. New York's approach is the most systematically data-driven urban rat control programme in the world: it knows where the rats are, why they are there, and what interventions work in which contexts. Mayor Mamdani has inherited this infrastructure and continued it. The lesson New York offers Paris is not a solution but a methodology: the rat problem is not a sanitation problem, it is an urban data problem, and the city that maps it most precisely is the one that can address it most efficiently.

Singapore 🇸🇬 — Singapore does not have a rat problem. This is not because Singapore is rat-free — it is not — but because the city has built a governance and surveillance infrastructure that keeps rat populations below the threshold of public visibility. AI-enabled camera networks in food centres and hawker stalls flag rodent activity in real time. Penalties for businesses with rat evidence are immediate and significant. Waste management is designed at the point of generation, not just collection, to deny rats consistent food sources. Singapore's approach is the most intensive state-level rat prevention system in the world. It would be practically and politically impossible to implement in Paris, where 61% of residents oppose lethal control and the rat has a legal advocate on the city council. But Singapore's data infrastructure — the real-time mapping, the AI detection, the predictive modelling — is exportable. A Parisian version of Singapore's rat surveillance system, stripped of its enforcement teeth, would at minimum give the city the count it currently cannot conduct.

Seoul 🇰🇷 — Seoul has used urban data mapping to address rat populations in its older residential areas — particularly the hillside neighbourhoods of Jongno-gu and Jung-gu, where traditional low-rise housing creates dense networks of alleys and gaps that rats use as highways. The city's rat mapping programme identifies burrow concentrations and correlates them with waste generation patterns, food establishment density, and sewer infrastructure age. The result is targeted intervention rather than area-wide poison deployment — which is both more effective and less likely to produce the resistance that has made half of Paris's rat population poison-immune. Seoul's specific contribution to a global rat hackathon would be the data-first methodology: before you trap a rat, map where it lives, what it eats, and how it moves.