Quality of cities, the magazine of the RATP group that shows THE CITY DIFFERENTLY.

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Dreaming cities

The city in RESET mode?

Reinventing the city’s ecosystem from a low-carbon perspective means devising a city that is more self-sufficient in terms of food supply, and thus emits much less greenhouse gas to deliver essential products to its residents. It also means a recyclable city, in which buildings, facilities, spaces and materials are reused, construction fills urban gaps, and occupants think in terms of time of use rather than ownership


The city goes green

In many places around the world, the concept of transition is replacing that of sustainable development, based on the foundation of urban farming and the many advantages it offers: short supply chains, “working together”, proper management of natural resources, and combating the emergence of heat islands.
From its origins in the UK in the early 2000s, the “transition towns” movement has become the spearhead of a radical urban transformation. Now present in more than 40 countries, transition initiatives have emerged in New York, Melbourne, Rio de Janeiro and Pondicherry. At the heart of the approach is permaculture, a way of farming modelled on the functioning of natural ecosystems, which creates another vision of the city by inviting residents to collectively adopt less oil-dependent lifestyles. For the founders of the movement, including Rob Hopkins, this first step taken together (growing local food for local consumption) leads to many others, giving rise to a multitude of citizen initiatives in all areas: accessible housing, local currency, combating discrimination, etc.

Urban farming has thus emerged from the shadows, to become a subject studied in its own right. This is demonstrated by the development of an international network of experts, initiated in 2020 by the University of Quebec in Montreal, Canada, and the University of Liège in Belgium. In early 2021, with the aim of speeding up work in this field and better highlighting what this type of farming can offer the city, the University of Liège inaugurated a research platform unique in Europe. Named Wasabi, it offers researchers and students a veritable playground of five hectares, divided into four sections (urban farming, biodiversity, botanical garden and rain garden). With spin farming (intensive farming over a very small area), Paff Box (1) and Groof (2), the urban farming of the future is taking shape here.

(1) Plant And Fish Farming Box: an aquaponics system that combines fish farming and growing plants in the water
(2) Greenhouses to Reduce CO2 on roofs: a 200 m2 greenhouse on the roof of a campus building that uses waste energy from the building to grow crops using hydroponics.


“Abandoned areas of the city offer tremendous potential.”

Rob Hopkins
Founder of the international transition towns movement

Is it still possible to change the city?

R.H. Of course, we could throw in the towel and say that it’s too late. But in my work and at my conferences, I try to persuade people that climate change can be a historic opportunity to create fun, beautiful and desirable cities. We have to “rewire” our brains, to let them see the possibilities rather than the dead ends. It is possible and it is already a reality. Look at what’s happening in Liège, Belgium, where the city is investing €5 million to completely redesign the food system with a “food belt” on land very close to the city.

Six other Belgian cities are considering doing the same thing, and in Marseille the municipality is buying land around the city for the same purpose. In Berlin, the amazing Prinzessinnengarten, a community garden installed on wasteland in 2009, is entirely planted in transportable containers, so that it can be moved if this land is ever built on. More and more cities are recognising food production areas as key parts of the urban fabric.

So in your view, these initiatives go much further than feeding or greening the city?

R.H. Yes, first because a garden can and should have several functions, it should be useful and productive. Each time we add something, we have to ask ourselves if this plant or this tree could also be a source of food, fibre, medicine, etc. It then becomes clear that these initiatives have a social impact. I visited a shared garden in Marseille. For many of the young people involved in it, it has become the centre of their social world, a place that organises events, that works with refugees.

Equally in Marseille, the amazing AprèsM, a former McDonald’s converted into a social and solidarity restaurant, and thus a “fast social food” joint, prompted the team responsible to ask themselves some very interesting questions. Serving 2,000 meals a week is great, but why not do so using locally grown food? And this will unlock a new economy, with producers able to supply this restaurant.

Does talking about these successes mean offering a different narrative, a new imaginary world?

R.H. We can see plenty of films and novels that present us with a horrible vision of the future. I took part in the documentary Demain by Cyril Dion and Mélanie Laurent, and the impact of this film was unbelievable. All of a sudden, in the commercial cinema circuit, people were going to watch a film on climate change.

I would like to make people long for a city that is beautiful, where biodiversity is preserved, where children play in the street. That should be the norm! To get there, we have to give people a taste of this desirable city, create “pop-ups tomorrows” of this low-carbon future everywhere.

Take the lift for the urban farm

Since 2016, the Parisculteurs de la Ville de Paris project has been encouraging the greening of the capital’s walls and roofs. Hydroponics at Ferme Lachambeaudie 1 (12th arrondissement), spirulina cultivation in the building on rue des Poissonniers (18th arrondissement), areas dedicated to urban farming within the Vaugirard workshops 2: numerous sites in the RATP real-estate portfolio have already been “greened”. The latest is the new maintenance workshop for metro line 14, in the heart of Docks de Saint-Ouen, which provides 9,000 m2 of roof space for use by a winner of the 4th edition of Parisculteurs.


Make way for virtuous circles

Ground is not an infinite resource. Consuming ever more land, demolishing to make way for new construction, building again instead of making better use of what already exists. It is all these old reflexes that circular urban planning seeks to transform, by favouring modular use of space. Since the 1970s, the car has shaped our cities, resulting in overconsumption of space to the detriment of agricultural land, and developers who offer a limited range of real-estate products: detached houses, apartment blocks, commercial areas, car parks, etc. Promoted by urban planner Sylvain Grisot, the notion of the circular city is inspired by the principles of the circular economy and combines several virtuous circles. The first is to avoid building, by making more intensive use of what already exists, as demonstrated by the Bertelotte university hall of residence, in Paris, in the 15th arrondissement. This 4,400m2 site, previously used as offices, has been refurbished to provide accommodation for 138 students, along with communal and co-working areas. Inaugurated in 2020, the building was designed using bio-sourced materials, notably straw.

The second circle of circular urban planning is to avoid demolition. Not only because demolition and rebuilding produce waste, but above all because demolition means losing material and grey energy. The third circle is avoiding urban sprawl, by increasing density or recycling, notably unused areas. According to the Paris Région institute, there are 4,200 hectares of wasteland in Île-de-France today, i.e. the equivalent of half of Paris. Finally, the fourth circle involves re-wilding, such as in the Nord Pas-de-Calais where the public land-management agency is developing temporary re-wilding of land between two real-estate development projects.
An example of virtuous circles in practice is the restructuring of RATP’s Jourdan, Corentin Issoire bus depot. Dating from the end of the 19th century, this industrial site has been transformed to accommodate a real urban complex consisting of a university hall of residence, social and private housing and green areas. A way of rethinking urban planning.


“We can build the city on the city, without taking up more space.”

Sylvain Grisot
Urban planner and found of the dixit.net agency

Is regenerating cities a necessity?

S.G. It is both a necessity, something must do it, and a possibility, we can do it, and this can be quite exciting. 80% of the city of 2050 is already around us and we have neither the time nor the resources to replace most of the building stock built before 2000.

In the face of the climate emergency, the usual approach of demolishing to build new buildings, better equipped for climate change or reversibility of uses, does not work.

So how can the city be redesigned without building more, without taking up more space?

S.G. By ceasing to prioritise new constructions and urban sprawl, which take up more and more land, and building further away from urban centres. The existing city, the one all around us, is full of resources and we already have all the solutions we need to transform it.

Contrary to a common preconception, there are unused spaces in cities that could be used to increase density in an intelligent way. We can also think in terms of time of use and not just space, by making better use of all those public facilities that are open for barely 30 hours a week, for example. Existing buildings can also be transformed, re-purposing rather than demolishing them.

You have called for land ownership to be separated from building ownership. How would the city benefit from this?

S.G. There is a “ground floor” crisis in the city. Separating the ownership of land and buildings would allow the creation of “commons”, managed as such. I am thinking, for example, of business parks that leave wasteland behind them, while farmland is being taken over next door for new buildings.

Taking the price of land out of the real-estate equation, treating it as a common good, would also mean taking a long-term view, generating new synergies between private and public players to enter into an industrial ecology approach.

The city as a subject of research and experimentation

In 2007, RATP chose architect Jacques Ferrier to design a 6,200 m2 office building on the Philidor Maraîchers site 3. Jacques Ferrier, who views the city as a fertile ecosystem, adopts an approach combining research and production, a resonant architecture that creates a new relationship with the planet, the city and its residents. His conviction? “What lasts is what can change.” A manifesto for buildings of such utility and simplicity that they can eventually be used for something other than their purpose in the initial project.

To read:
La ville machine, Jacques Ferrier – 2021, an essay questioning the dominant role that technology has taken on in our city lives, and calling for the human being to be put back at the centre of the urban project.
Manifeste pour un urbanisme circulaire, Sylvain Grisot – 2021, a manifesto for circular urban planning, offering concrete alternatives to the sprawling city.

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