Boulogne-Billancourt was divided between rich Boulogne and working-class Billancourt particularly with regard to housing since the beginning of the twentieth century. The socialist local government of Alphonse Le Gallo, the mayor of the city, accepted the increasing intervention of private developers in housing construction to diminish municipal expenditures. In recompense, it approved their construction of lots of luxury housing units. Because of this timid budgetary choice, it provided the smallest number of low rent housing units of the eighty cities in the department of the Seine despite the many potential housing sites vacated by enterprises such as Renault, which made semi-skilled workers leave the city for poorer regions after the end of the 1950s. Consequently, the social divide was not resolved but shifted progressively to other cities or regions contrary to the SFIO’s agenda.