In France, the local use plan, called " Plan Local d'Urbanisme ", includes zoning rules which are juridically binding, while, for example, "plans in the UK are not part of the law but are made under the law" (Cullingworth, Nadin, 2006, p3). But it appears that even in France, the actors involved on real estate and land markets contribute to create new flexible ways to use and apply the rules of law. For local authorities, it constitutes an opportunity to control and finance urban development, including public equipments, social housing, qualitative urban design... In this presentation, we show that this approach of housing markets enable us to better understand why and how local public authorities in France contribute to write land use plans, and then negotiate its application, even if the zoning plan is supposed to be legally binding. It appears that the rules of law have a major impact on social relations between actors who contribute to produce housing. But neither this rules of law, nor economical laws, eradicate other forms of regulations, which can only be understood by paying more attention to the ways actors interact on land and housing market.