Segregation has been widely discussed by social scientists and especially by urban geographers and planners over the past decades. However, regardless of their focus, most of these studies view segregation as an obvious case of spatial injustice. I argue that this implicit relationship between segregation, (in)justice, and space needs to be reexamined. This paper approaches this task by reviewing an interdisciplinary body of literature (including geography, sociology, history, political sciences, and philosophy) that deals with segregation without (explicitly) tackling the issue of justice. Focusing on the case of poor, segregated neighborhoods in France, this paper examines the question of whether the segregated city is essentially unjust, analyzes the extent to which segregation is a spatial injustice, and identifies segregation’s underlying (spatial) causes. It will then question the dominant contemporary discourse that holds that the Just City should be a diverse city at the neighborhood scale.