In the framework of model-based design formal modelling, verification and sim- ulation of safety-critical systems are supported by several methods and tools. Interfacing these tools often becomes challenging for heterogeneous systems. The FMI standard enables integration of different simulation tools through artefacts called Functional Mockup Units (FMU) [1]. The FMI standard is mainly based on the concept of scalability of the simulation as it deals with heterogeneous cyber-physical systems. The combination of discrete behaviour and continuous- time environment is a common case study in hybrid simulation. Moreover, an- other aspect of the FMI is to enhance the capability of the tools. Thus, a collab- orative simulation between the Rodin [2] and Ptolemy [3] is leveraged by both platforms. While Event-B is enhanced by new models of computation of Ptolemy, Ptolemy leverages the expressivity and properties validation (theorem/invariant proofs) implemented by Event-B. The main rationale of the co-simulation be- tween Event-B and Ptolemy relies on the intention of dissimilarity and com- plementarity of the modelling viewpoints. Event-B provides formal modelling by specifying conditions, actions and properties that manage discrete event be- haviour, whereas Ptolemy gives a structural viewpoint in terms of actors, com- ponents or functions with relation to concerned behaviour. Thus, the association of Ptolemy and Event-B puts together structural and formal aspects.