There is growing interest in integrating rule based reasoning with other resolution paradigm, including constraint programming. This paper proposes three hybrid techniques which reinforce standard reasoning technique of rule based system with constraint satisfaction techniques. Firstly, we describe general principles of our multi-core expert system. Furthermore, we explain the various manners for communication or collaboration between a CSP solver and an inference engine of expert system. Secondly, we present the hybrid inference mechanism, and we give the principle of these approaches. Then, we analyze these approaches emphasizing the properties of each one.