The propensity to migrate within France changes a lot with age and occupational status. This paper aims to rationalize these differences by investigating the role of barriers to mobility in localisation strategies. We use the model developed by Schmutz and Sidibé (2019) to identify the roles of mobility cost, and spatial frictions (that decrease workers ability to compete for distant job opportunities). The model is estimated with a matched employer-employee panel dataset that describe labor market transitions within and between the 30 largest French cities between 2002 and 2007. Our results suggest that: (i) mobility costs are 20% higher for older workers, (ii) mobility costs are 15% higher for blue-collar workers, (iii) differences in friction parameters seems to be the main drivers of the mobility gap among age and occupational groups, (iv) a large share of the mobility rate gap results from the relative immobility of unemployed older workers and blue-collar workers.