Blache [1] introduced Property Grammar as a formalism where linguistic information is represented in terms of non hierarchical constraints. This feature gives it an adequate expressive power to handle complex linguistic phenomena, such as long distance dependencies, and also agrammatical sentences [2]. Recently, Duchier et al. [3] proposed a model-theoretic semantics for property grammar. The present paper follows up on that work and explains how to turn such a formalization into a constraint optimization problem, solvable using constraint programming techniques. This naturally leads to an implementation of a fully constraint-based parser for property grammars. 1 Note that a first experiment of constraint-based axiomatization of PG was done by Dahl and Blache [9], we give more information on this later in section 7. 2 Several attemps at characterizing syntactic trees through a system of constraints were developed in the late nineties. Among these, one may cite D-Tree Substitution Grammar (DSG) [10], and Tree Description Grammar (TDG) [11]. The main difference between these formalisms and PG is that the latter has been designed to provide a way to handle agrammatical sentences. Furthermore, in DSG and TDG, constraints are expressed using dominance-based tree descriptions, while PG's constraints are applied to syntactic categories.