The mineral Place de la Concorde should regain its former greenery

The largest square in the capital, created by Louis XV, is now reduced to a "sad role as a traffic roundabout," according to Paris City Hall's Anne Hidalgo, who unveiled the winning project for the redevelopment of this historic axis on Thursday.

At the heart of the redevelopment: the greening of the former royal square, restoring the old ditches planted in 1757 by the architect Ange-Jacques Gabriel, its lawns, and its connection to the Seine, currently hindered by access to the underground road tunnels.

"A bold yet humble greening gesture that addresses climate issues while preserving the historical coherence" of the square, which has been listed as a historic monument since 1937, praised the socialist mayor.

The project was chosen by a jury of the commission she created a year ago, under the chairmanship of former Minister of Culture Jean-Jacques Aillagon and in which presenter Stéphane Bern and climatologist Jean Jouzel participated.

Throughout the site, the digging and planting of historic ditches "will echo what it was like in the 18th century," before they were filled in in the mid-19th century, explained award-winning architect Philippe Prost.

They will each be 22 meters wide - or 2,8 hectares out of a total area of ​​8 hectares - with a variable depth depending on the subsoil, added Philippe Prost, designer of the Ring of Memory of Notre-Dame-de-Lorette in Pas-de-Calais.

The ditches - which will not be walkable - will "help manage flooding, thanks to their storage capacity for five days of intense rain," explained award-winning landscaper Anne-Sylvie Bruel, designer of the Bottière-Chénaie eco-district in Nantes.

Eight degrees cooler

"The square will regain some of its natural, permeable soil," giving hope for a drop in ground temperature of up to 8 degrees on one of Paris's main heat islands, explained Christophe Najdovski, deputy mayor of the City Hall in charge of green spaces.

The famous paving stones will be preserved, but with new, lighter materials to reflect solar radiation, according to Anne-Sylvie Bruel.

You can sit on one of the four large open lawns to admire the Luxor obelisk from the central reservation. But in summer, you won't have to count on the shade of the trees, which will remain absent from the square, so as not to obscure the grand perspectives or the facades of Gabriel, including that of the Hôtel Crillon.

Some 130 trees are planned to be planted along the banks of the Seine, which the project aims to bring closer to the square, to recreate the promenades of yesteryear. This involves removing the access tunnels to the Concorde underground tunnel, which allow motorists to reach the Georges Pompidou Way from the Avenue des Champs-Élysées, and which hinder access to the river.

Sidewalks will be widened on the upper platforms, with stairs providing access to the lower platforms. There will be dedicated lanes for buses and bicycles, added Anne-Sylvie Bruel, without providing further details.

The stated objective: to reserve 66% of the space for pedestrians in this square in the 8th arrondissement, the entry point to the limited traffic zone (ZTL) which has banned through traffic in the first four arrondissements of the capital since this autumn.

"Traffic is already very light on Rue de Rivoli upstream from Place de la Concorde," said Ariel Weil, the mayor of Paris Centre.

Traffic will continue to operate at half-gauge, as has been the case since the 2023 Rugby World Cup.

The work, estimated to cost between 35 and 38 million euros, will begin "as soon as possible" and be completed within two or three years, said Anne Hidalgo.