When heatwaves strike France, Paris is rarely the hottest location in the country, yet the capital is significantly over-represented in statistics regarding excess deaths during periods of extreme heat. During the June 2026 heatwave, public health authorities reported that deaths in the Paris region doubled. While soaring temperatures proved fatal across the nation, the nationwide excess death figure stood at approximately 30 percent, marking Paris as a clear outlier in terms of heat-related fatalities.
Meteorological maps from the June event confirm that Paris was not the hottest part of France. While temperatures in the capital repeatedly topped 40C, regions in the south of the country saw temperatures reaching 43C, and the south-east experienced a much longer duration of extreme heat than northern France. This raises a critical question: what makes Paris so uniquely dangerous when temperatures rise?
The city suffers from a pronounced "heat sink" effect, a phenomenon common to all urban environments where concrete absorbs heat and reflects it back. This is exacerbated by human-generated heat from vehicles and air conditioning units. Paris faces two specific geographical disadvantages: it lacks sufficient green space, and the city sits in a hollow, which traps hot air. Consequently, Paris is regularly 10C hotter than the surrounding area during a heatwave.
A primary issue is that Paris was simply not designed for extreme heat. Cities like Nice or Montpellier, which often experience equal or higher temperatures, are built with hot summers in mind, featuring narrow, shaded streets, buildings with thick walls, small windows, and abundant public shade. Paris, however, was not designed this way because it historically did not experience such high temperatures. Some aspects of its urban design actually function to keep heat in rather than letting it escape. As the planet warms, even northern cities are now exposed to temperatures once reserved for the Mediterranean coast.
The city's housing stock is also largely energy-inefficient. The June death toll, which covers the greater Paris region, includes poorer suburbs filled with poorly constructed modern tower blocks that turn apartments into furnaces during the summer. In these low-income areas, most residents are renters who cannot make major structural changes to their homes and often cannot afford to purchase or run air conditioning units. Samira, a resident of Ris-Orangis in Essonne, told the Guardian in June that the blazing sun hits her windows all day, making it impossible to breathe. She described her home as an oven, noting that she can only use a fan in short bursts due to electricity costs, leaving her exhausted and struggling to protect her son from the heat.
Even in the capital's wealthiest districts, the architecture works against residents. The city's iconic grey roofs are made of zinc, which is a very poor insulator. During the June heatwave, a video went viral showing a man cooking a crêpe on a zinc roof, highlighting the extreme temperatures these surfaces reach. This is a serious concern, as residents living in top-floor apartments directly under these roofs are four times more likely to die during a heatwave than those living on lower floors.
Air conditioning remains rare in Parisian homes. While offices often have cooling systems, the majority of schools and hospitals do not. Because most people rent their homes, they are often left waiting for landlords to install cooling, or they must rely on expensive and inefficient portable units. Furthermore, while Paris has a younger-than-average demographic, the surrounding suburbs, particularly in the département of Seine-Saint-Denis, suffer from high rates of poverty and deprivation. These residents are more likely to live in unsafe housing, lack access to green spaces or swimming pools, perform outdoor work, and suffer from chronic health problems.
The city of Paris has long recognized these challenges. In 2023, officials conducted a series of emergency planning exercises to simulate the impact of the city reaching 50C. From these exercises, a resilience plan has been developed, and ongoing work is underway to plant more trees, create additional green spaces, adapt existing buildings, and improve overall heatwave preparations.
Although the soaring temperatures proved deadly all over the country, the nationwide excess death figure was about 30 percent, making Paris an outlier in terms of heat fatalities.
READ ALSO: Grass roofs and siestas: How Paris is preparing for the day temperatures hit 50C
