The Institute for Urban Planning and Development (IAU) found increasing gentrification in the historic heart of Paris as poverty concentrates in the suburbs or satellite towns of the region.
The Ile de France, with Paris at its centre, accounts for 30 percent of the national economy and is also home to the biggest immigrant population, where poverty concentrates.
A total of 15.9 percent of people lived below the poverty line in 2015 – one percentage point higher than the national average — up from 12.3 percent nine years earlier, the study said.
Average income fell in 44 areas of the capital region between 2001-2015 in places such as Grigny, Clichy-sous-Bois and Aubervilliers where both unemployment and the foreign-born population has increased, the study said.
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In contrast, the highly qualified and managerial class occupies central Paris and its wealthy western suburbs.
“Wealth is more noticeable and more concentrated than poverty,” said Mariette Sagot, the report's author. “The wealthy tend to stick together more so than the poor”.
The main driver of rising inequality is property prices, which have increased 50 percent in Paris over the last decade.
“Social differentiation is mainly a reflection of the housing market,” said Martin Omhovere, director of the institute's housing department. Social housing is “the only way poorer households can live in the centre”.
Poverty in the suburbs was highlighted in “Les Miserables”, which featured at the Cannes film festival last month.
French actor-director Ladj Ly, shot the film in a social housing project in a northeast Paris suburb where nation-wide riots broke out in 2005.
“This a film is a warning cry,” Ly said at the festival, urging President Emmanuel Macron to watch.
Macron has faced seven months of protests by France's “yellow vests”, who accuse him and his government of increasing inequalities through pro-business policies.
The centrist leader has made tackling high unemployment his main priority, seeing it as the biggest source of inequality.
In 2015, Prime Minister Manuel Valls warned of “apartheid” in Paris, drawing attention to the wealthy, mostly white centre and the immigrant-heavy and poorer areas that ring the capital.
The region's poorest location, Seine-Saint-Denis, boasts a number of sites for the 2024 Paris Olympics, in a bid to regenerate areas with high crime and unemployment.