MAINTENANCE. “We must change the city’s manufacturing model” to meet the challenges

Sylvain Grisot is an urban planner in Nantes ( agency) and co-author, with the president of the National Council of the Order of Architects, Christine Leconte, of Let’s fix the city! a guide to adapt cities and territories to the climate, environmental and quality of life challenges of the 21st centurye century.

Why do we need to rethink cities?

We will be confronted, during the XXIe century, to climate crises, biodiversity, but also resources (1). When you are a city “maker” (urban planner, local elected representative), you are faced with this triple problem because building requires raw materials (water, cement, etc.) which risk being lacking, just like space.

However, the city as it has been built in recent decades has consequences in terms of greenhouse gas emissions, through the construction and life of its buildings, but also because of the mobility induced by the sprawl urban (2). The city’s manufacturing model must be changed.

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photo the baud chardonnet neighborhood under construction in rennes will eventually have just over 5,000 inhabitants.  © archives marc ollivier, west-france

The Baud Chardonnet neighborhood under construction in Rennes will eventually have just over 5,000 inhabitants. © Archives Marc Ollivier, West-France

Are you saying that new construction should be stopped?

We have, for fifty years, industrialized the fabric of the city by concentrating on the new, with urban sprawl or large urban renewal operations.

However, there are plenty of alternatives: make denser houses (adjoining, as in Amsterdam) or collective, but with common areas as meeting places: large halls, convivial rooms, interior courtyards, green spaces… house is not the enemy, contrary to what the minister said. The enemy is the new house, in the new housing estate, even further than the previous one, which uses agricultural land and intensifies automobile mobility to reach work, 45 minutes away.

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Individual houses that are no longer adapted to current challenges

How to rebuild the city on itself?

The house surrounded by a plot of 800 square meters is no longer adapted to the challenges of the century. Especially when you know that two thirds of individual houses in France are under-occupied.

Inhabited by households whose children have left, they are no longer suitable for the seniors who live there, as they are far from local services. They need a global thermal rehabilitation and, on this occasion, another house could be created in the large garden. This is one example of soft densification among others (like replacing two houses with a small building or adding a floor to a house), without going through a new artificialization of the periphery.

Is it the end of the French dream of a pavilion with a garden?

When the lodgers ask the French whether they prefer a little house in the meadow or a rabbit cage, of course, they answer the house. But if you dig deeper, this translates above all a demand for calm, access to an outdoor space and proximity to shops and services.

What is specific to the city with schools, employment… The question is to have an urban real estate offer that inspires and meets the real needs of the inhabitants. It is necessary to get out of the constructions of large standardized sets, bought by lessor owners to reduce tax. These accommodations are not made to be inhabited or to last over time.

photo billboard announcing the construction of a building in place of two houses, in rennes.  © west-france

Billboard announcing the construction of a building in place of two houses, in Rennes. © WEST-FRANCE

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Densification as a solution?

How can the densification of a neighborhood be made acceptable to its inhabitants?

It is necessary to take advantage of the construction of a building to rethink the district as a whole, to improve its public spaces, the vegetation and to make the soil permeable.

The elected representative must be the guarantor of a real dialogue between the lessor/developer and the inhabitants. The latter must no longer simply be consulted for the color of a facade or to grant them one floor less in the future construction. We need real consultations upstream, and explanations on everything that this project will bring to the district: green spaces, shops on the ground floor…

The city has become hostile to children?

The city was designed for the car. This has led to a loss of autonomy for the children. In three generations, the street which was a space of freedom for them has become a danger zone. And they now discover it from the back seat of the car that takes them from home to school.

In Paris, 50% of public space is dedicated to the car [rues, stationnement sur voirie, parkings], parked 95% of the time. It takes up the space we need to create cycle paths, green spaces… So many facilities to prepare for stormy periods and heat waves that will multiply.

Cities facing climate change

Are cities more threatened than the countryside by climate change?

During periods of intense heat, the temperatures of the current city, which is very mineral (concrete, asphalt on the ground), drop little at night. But that is the danger for humans. It is necessary to de-waterproof the soil to store rainwater which will evaporate and bring freshness during periods of heat, and to rethink construction materials.

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It is necessary to repaint the roofs in white so as not to store the heat, and to equip each district with benches in shaded parks, paddling pools or water mirrors. The city of tomorrow is also one that will have local facilities to allow everyone to cool off and keep in touch.

(1) IPCC report (Group of Experts on Climate Change) published on February 28, 2022.

(2) The building is the second source of greenhouse gas emissions in France.


1976. Born in the Paris region.
1998. Sciences Po Aix.

1999. DEA of anthropology.

2004. Master’s degree in urban planning, territorial project and sustainable development.

2007. Master of business administration.

2015. Creates the town planning office dixit.netIn Nantes.

2021. Publish Manifesto for circular urbanism (Apogée 2021 editions), in which he invites city stakeholders to transition to a frugal, close, resilient and inclusive city.

2022. Let’s fix the city! Proposals for our cities and territoriesApogee editions, €10.