This chapter presents the modeling and simulation works applying UrbanSimE in Paris case study. This is the most important application of UrbanSim worldwide with respect to the size of the region and of the project evaluated, data availability and complexity. The rich available data allowed us to make different econometric analyses and to implement several theoretical insights previously presented in this handbook. The model has been successfully used in an applied study concerning the Grand Paris project, which can be considered as the most important investment plan in the transportation system of the region since the construction of Paris subway network at the beginning of the 20th century.