National audienceThe middle classes are today attracting renewed attention not so much because of their hegemony but rather because of the growing difficulties that some of them are experiencing. As a result of a vast enquiry into the working population of France, this paper draws attention to the mismatches existing between belonging to the middle classes on the basis of socio-professional status and the actual material conditions of living and housing. This focuses attention on the depreciation of incomes, increasing necessary costs (primarily housing) and most especially the professional downgrading of some middle class households. The striking internal disparities within this group are marked by the differentiation of their residential ...