We develop a framework called Agent and Artefact forMultipleModels coordination (AA4MM) . It is is intended to make the design and the implementation of complex systems simulation mod- ular and decentralized. Our main goal is to reuse existing models and simulators and to make them interact in order to simulate dierent levels of abstraction. The main constraint is that people involved into the design process do not have to care about anything else but modelling. Coordination challenges remain to the framework. This report presents the event-B specication of the coordination model proposed in [SCC10]. Its goal is to check that the system is never blocked (no deadlock): no simulator is waiting for another indenitely.