In the knowledge economy, the rise of new social environments is blurring the conventional separation between the first place (home), the second place (work), and the third place. The paper aims to construct a typology of places in the knowledge economy. The research methodology is based on an exploratory case study approach investigating the social environments in Paris (France) that don’t fit in the traditional typology of places. The paper finds that the new social environments in the knowledge city can combine elements of the first and second place (coliving); of the second and third place (coworking); and of the first and third place (comingling). Furthermore, the combination of elements of the first, second, and third place in new social environments implies the emergence of a new place, the fourth place. The paper contributes to understand how the knowledge economy is changing the nature of places in the global post-industrial city.