The objective of this paper is to outline the determinants of municipal land zoning in favor of agricultural and natural land conservation through a parsimonious allocation of land to urban development. We first rely on an abundant theoretical and empirical literature, especially on Solé-Ollé and Viladecans-Marsal (2012) and on a purposely designed field study of municipalities in Southern France to propose a theoretical model better suited to the French framework. The model is then econometrically tested, to account for possible selection bias. This empirical validation highlights the role of agricultural characteristics and the unexpected effect of electoral competition.