The Local Urbanism Plan (LUP) set, within the respect of the norms hierarchy, the using rules of the soil on his territory. This hierarchy is constituted by a number of norms and principles which kept growing more and more since it was decentralized. Even though they’re different, these norms are all applicable in the same way to the LUP, with some exceptions. The LUP has to be compatible with their dispositions. This layout apparently coherent hides a high amount of imperfections. Higher norms, but not less generals, can as well be expressed in precise terms, mixing elasticity and rigidity, precision and imprecision, certitude and incertitude. Since nominative reports are not precise, they share in the first place the validity determined by the higher order, but also the incertitude affecting it. They don’t exclude the possibility it will intensify, meaning it could lead to the conformity, and neither have they excluded the weakening leading to a simple take into account. Then the LUP has to deal with these excess of rigor or weakness and to take into account the intellectuals, accessible, relatively stables, and legally secured rules. But this exercise is very tricky and a lot of towns are concerned since they cannot adopt an interpretation totally conform to the spirit of the superior norm without escaping the reproduction of the ambiguity which characterize this norm at the LUP level. As a result, LUPs become hardly decipherable and legally vulnerable since their recipients, which have hard times to give a precise meaning to this rules and characterize with precision which are applicable to a given time, are always ready to contest it. In this context, the judge received new capabilities in order to temper the litigation impact about the LUP legal security. Thus, alternatives to its cancelling are added to the drastic monitoring of the admissibility conditions of the recourse against the LUP.