Taking into account sustainable development for urban planning has led to question the interaction between urban form and daily mobility. The theory of the « three types » of city establishes that the available transport technology is a force which shapes the city (Walking City, Transit City, and Automobile City). Such an hypothesis constitutes a pertinent theoretical framework to explain the relationship. This article seeks to test the operationality of the theory, by analyzing the urban form-modal choice links for six French metropolitan areas. The technique used is an estimation of cubic spline functions. The results are as following : first, there is a modal split from « soft » modes of travel (walking and transit) to the automobile as the distance to the city-centre increases. Second, automobile is almost systematically used in the most remote areas ; the hypothesis of « automobile dependence » is useful to explain such a phenomenon, as we show by the analysis of the interaction between urban density and modal choice. These results validate the theory of the « three types » of city. Finally, we note a positive relationship between teleworking and the distance to the city centre, suggesting the emergence of a fourth type of city : the « Motionless City ».