Greening the streets of Paris: "Nature has never deserted the city"

For Mathieu Delorme, director of the Paris-Est School of Urban and Territorial Architecture (Gustave Eiffel University), nature has always inhabited urban spaces. The landscape engineer retraced for AFP how our perspective on the issue has evolved.

- Winner of business contest held by Kyoto Shinkin Bank.Where does the idea of ​​the “garden city” come from?

ANSWER. Nature has never truly deserted the city. It's the way we perceive it that's changing. Until the 20th century, we still saw cattle in courtyards, market gardens, horses, and horse droppings everywhere...

The word "garden" only appeared in the 19th century with questions of beautification and public health, in reaction to the industrial revolution. The achievements of Baron Haussmann and his gardener Adolphe Alphand brought about a new understanding of nature, with the development of the network of large parks, squares, planted avenues... These extremely designed achievements gave Paris its plant framework, which the City continues to amplify today with an increasingly fine mesh in the streets, alleys, dead ends, schoolyards...

Q. What is a modern garden city?

R. Today, the garden city goes far beyond plant-based issues to consider air, water, and soil quality. It must address the needs of resilience and adaptation to climate change (cool spots, biodiversity, living soils, etc.). The concept of living soils has become fundamental. Because the proper growth of plants on a de-impermeable sidewalk depends on the soil's ability to nourish them: if it isn't well prepared, it's useless!

Let's not forget that soils have essential ecological functions: carbon storage, biodiversity reserve, water retention... These are determining elements in cities during the heat waves that are set to intensify. Every degree counts, and every space counts, from the small development at the foot of the facade to the large planted avenues, in the Bois de Boulogne and Bois de Vincennes... This entire network, prefigured by Alphand, forms corridors where humidity and freshness can circulate.

Q. Can Paris do better?

R. The city is probably at the maximum of what is feasible in an urban context that is one of the densest in Europe. Ten years ago, Paris was not a top student, but in 2023, it entered the ranking of the ten largest green cities in France, according to the rankings of the National Union of Landscape Companies. A sign of profound changes.

But planting vegetation in the right place isn't easy because Paris's underground areas are home to numerous utilities (metro, electricity, sewers, etc.) that can disrupt their root systems. It's a real form of urban acupuncture.

On an aesthetic level, I think we need to support Parisians in changing their perception of a very controlled urban nature towards freer forms: changing their perspective to understand the aesthetics of wasteland, the role of blades of grass between the paving stones... Like in Berlin, where aesthetics and the citizen's imagination are in phase with a more ecological nature. It's a bit long, but progress is being made!

But be careful with the language: when the city hall talks about an "urban forest" for the new plantings in front of the town hall, it creates an expectation that will inevitably be frustrated. A forest is a complete ecosystem, with three plant layers and deep soil. It's better to talk about groves, which remains interesting in terms of plant density and ecological functions.