What are cities doing to become more sustainable? A sustainable city concept integrates green practices, green spaces and supporting technologies into the urban environment to reduce air pollution and CO2 emissions, improve air quality and protect natural resources.

Cities can do many things to support sustainable practices:

• Facilitating car-free travel
• Adding charging stations for electric vehicles
• Providing access to public resources and green spaces
• Improving water conservation and wastewater management
• Supporting urban agriculture
• Implementing green architecture
• Increasing the “social mix”

Even before the coronavirus struck, there were signs that more and more people in the US, for example, were moving to the suburbs, the so-called “belts”. These moves were motivated by a desire to "live differently".
After years of growth, New York City's population had begun to slowly decline by 2017.
Chicago and Los Angeles have also seen their populations plummet in recent years, while the economy has recovered in the suburbs and elsewhere. Other major cities have seen their growth virtually stagnate.
According to David Rosner, co-director of the Center for the History and Ethics of Public Health at Columbia University, historically, epidemics have played an important role in determining where and how people live in New York and other cities.
After the cholera epidemic that hit the city in the 19th century, for example, people began to leave lower Manhattan for other areas if they could afford it.
Suburban communities began to separate according to social class and population movements.
Closer to home, in France, job and housing applications in the outskirts of cities have tripled between spring 2020 and the end of last year.
Finally, let’s not forget the fundamental need for housing. A study by the ESCP Junior Conseil for the Federation of Property Developers shows, for example, that France would need to build almost ... 5 million housing units over ten years.

We could have taken the example of New York or Miami, but Paris also reflects the fundamental change in the real estate market in the world, a transformation that has accelerated since the onset of the Covid-19 crisis.
With the arrival of the Grand Paris Express and its 200 km of tracks and 68 stations, the Parisian suburbs will undergo changes by 2030.
This project will also result in the creation of major business centres and commercial and research areas. The economic development of Greater Paris will be based above all on the major centres of activity served by the new trains, such as La Défense (financial centre), Plaine Commune (cultural and creative centre), Roissy-Charles De Gaulle (international trade centre), Le Bourget (aeronautical centre), and the Saclay plateau (new centre of scientific and technological innovation).
These clusters ought to contribute to the attractiveness and competitiveness of the Greater Paris region on a global scale.
Each pole should generate thousands of jobs and the construction of housing (70,000 units per year are planned over a period of 25 years, 30% of which will be social housing).
INSEE predicts that the population of Greater Paris, estimated at 7 million inhabitants, will be younger (see Point d) and will be multiplied by 1.7 by 2030. Greater Paris is organised into 12 territories of at least 300,000 inhabitants and covers 814km², i.e., eight times the area of the City of Paris.
The Greater Paris project has and will change the real estate market by moving part of the transport system outside of the city. The demand for housing has obviously followed, as have the prices...

According to data from the Notaires du Grand Paris, the market for housing in the greater Paris region (Yvelines, Essonne, Val d'Oise and Seine-et-Marne) continues to soar.
Logically, prices follow the craze: up by an average of 4.8% over one year in all the departments of the greater Paris area.
More broadly, the 7 million inhabitants living in the metropolis produce 75% of regional GDP and 30% of national GDP. With the creation of the Grand Paris Express, the metropolis is likely to generate greater economic benefits.
In the long term, the Île-de-France Chamber of Commerce and Industry estimates that Greater Paris will add €140 billion to France's GDP and more than €60 billion in public revenue per year by 2030.

The Covid-19 health crisis has accelerated an existing trend: the expansion of large cities through the "annexation" of neighbouring municipalities. These new megacities will help to relieve congestion in the city centres, which were suffocating, and refashion the way we work and live.