Since 2021 in France, the "ZAN" objective has been enshrined in law and binding. Before reaching it completely in 2050, the country must halve, every ten years, the rate of nibbling by the city of natural soils, harmful for the environment, the climate and biodiversity.
For developers, whose economic model historically consists of buying "bare" land - not artificial -, building on it and reselling it, "it's a change of model which is not necessarily serene", explains Vincent to AFP. Le Rouzic, director of studies at the Fabrique de la Cité, the Vinci group's think tank.
The real estate subsidiary of the construction giant wants to be a pioneer in this area. It has set itself two objectives for 2022: to achieve ZAN by 2030, calculated according to a metric developed within the group, and to achieve, before 2030, more than half of its turnover in urban recycling.
"A way of rethinking our profession", explains to AFP the CEO of Vinci Immobilier, Olivier de la Roussière.
The group now refuses the most artificializing projects with regard to the built surface. “Typically, a housing estate with individual houses, roads, etc. That is something that we have really banned,” says Olivier de la Roussière.
"We build a lot more today on areas that are already artificialized, we look for this type of land; and when necessary, we deartificialize", he explains.
Clean up
This has consequences on the economic balance of operations.
"With the scarcity of land, these are sometimes equations that are complicated to find, especially since we have been in a very strong increase, for two years, in the cost of materials", testifies Caroline Delgado-Rodoz, General Manager Large projects of the promoter OGIC.
For the construction on the wasteland, Vinci Immobilier has had to hire a pollution control specialist, and provides more funds, on each site, to deal with any hazards.
"A polluted site costs money, a site to be demolished too. These are much more advanced studies", details Olivier de la Roussière. "There is a lot of work to check the costs of everything related to rehabilitation, depollution, asbestos removal..."
The group is also targeting old office buildings made obsolete by new ways of working or their distance from city centers.
"There will be office wastelands as there have been barracks wastelands, as there will be commercial wastelands, etc. There are plenty of reasons why we can have wastelands", wants to believe Olivier de la Roussière.
"Yes, obsolete buildings are starting to interest, especially in Île-de-France, there is starting to be competition," said Marc Villand, president of the Federation of Ile-de-France property developers, during a press conference. But "when we take back these old structures, they are often between 20 and 35% more expensive than new".
Density
The constraints of the ZAN also raise questions of acceptability, in a context where new constructions often arouse opposition from local residents.
"With the question of ZAN, what happens is also the acceptability of the height and density in the islets", estimates Caroline Delgado-Rodoz.
"We don't want to be tall, we also want nature in the city... but the land being what it is, we sometimes have to create density to create ventilation in the city, and that's all this balance that must be found”, she adds.
"When you arrive in a territory, you cannot arrive with a project that does not present advantages for the environment, for the local residents", judge Benoît Fragu, director of development of the property company Covivio. "You have to offer people a project that will be acceptable. The project where you are going to concrete the city is over."