Until World War II, Paris remained pretty much as Haussmann had left it. Housing conditions showed little sign of improvement. There was even an outbreak of bubonic plague in Clignancourt in 1921. In 1925, a third of the houses still had no sewage connection. Migration to the suburbs continued, with the creation of shantytowns to supplement the hopelessly inadequate housing stock. After World War II, these became the exclusive territory of Algerian and other North African immigrants . In 1966, there were 89 of them, housing 40,000 immigrant workers and their families. 

Only in the last thirty-odd years have the authorities begun to grapple with the housing problem, though not by expanding possibilities within Paris, but by siphoning huge numbers of people into a ring of satellite towns encircling the greater Paris region. 

In Paris proper this same period has seen the final breaking of the mould of Haussmann's influence. Intervening architectural fashions, like Art Nouveau, Le Corbusier's International style and the Neoclassicism of the 1930s, had little more than localized cosmetic effects. It was devotion to the needs of the motorist - a cause unhesitatingly espoused by Pompidou - and the development of the high-rise tower that finally did the trick, starting with the Tour Maine-Montparnasse and La Défense , the redevelopment of the 13e and, in the 1970s, projects like the Pompidou Centre , the Front de Seine and Les Halles . In recent years, new colossal public buildings in myriad conflicting styles have been inaugurated at an ever more astounding rate. 

When the Les Halles flower and veg market was dismantled, a sign posted during its redevelopment lamented, "The centre of Paris will be beautiful. Luxury will be king. But we will not be here." Indeed, the city's social mix has changed more in twenty-five years than in the previous one hundred. Gentrification of the remaining working-class districts has accelerated, and the population has become essentially middle-class and white-collar