We outline the determinants of local public policies for farmland preservation and urban expansion. We first rely on the literature and on a purposely-designed field study of municipalities in Southern France to propose a theoretical framework better suited to the French situation. The model considers aspects of land consumption, two interest groups as well as the median voter, and is then econometrically tested. We confirm the expected effects of certain socio-demographic determinants; highlight the impact of municipal budgetary considerations and the role of the agricultural sector. We also find more counter-intuitive determinants, like local political regime or unbalanced neighbouring relationships