Our paper contributes to the analysis of the transformation of middle classes in Europe by linking the issue of spatialization of class at the transnational and urban levels with the question of mobility and skilled migration. We therefore analyse the migration motives and urban practices (lifestyle and residential choice) of about ninety mobile middle class French nationals in London and middle class British nationals in Paris. The respondents belong to various fragments of an emerging European transnational middle class, whose diversity is reflected in their reasons for moving and their experience in the new city. Drawing on the concept of elective belonging, we argue that both the transnational and urban levels are important for class making mechanisms. Our results illustrate the relevance of the transnational level, i.e. cross-border mobility, for the making and reproduction of middle-class status. At the same time, the urban level – both the city and neighbourhood – is a crucial element that facilitates or obstructs middle-class practices, e.g. related to lifestyle or residential choice. For our respondents, multicultural London presents the economic capital of Europe with abundant professional opportunities, while Paris is viewed as a provincial city, liked for its beauty and lifestyle, but economically far behind London.