This paper deals with the proposal of a new model based on Agent Petri Nets (APN) to specify interactions among agents in Multi Agents System (MAS). Indeed, an agent approach requires a powerful and expressive formalism that allows him to model the behavior of a set of agents that interact. We are modeling some variants of FIPA standard protocols. Our Models are found based on communicating cognitive agents. Each Agent is capable of perceiving their environment partly and building, sending and receiving messages.