International audienceThe development of complex multi-domain and multi-physic systems, such as Smart Electric Grids, have given rise to new challenges in the simulation domain. These challenges concern the capability to couple multiple domain-specific simulators, and the FMI standard is an answer to this. But they also concern the scalability and the accuracy of the simulation within an heterogenous system. We propose and implement here the concept of a Matryoshka FMU, i.e. a first of its kind FMU compliant with the version 2.0 of the FMI standard. It encapsulates DACCOSIM – our distributed and parallel master architecture – and the FMUs it controls. The Matryoshka automatically adapts its internal time steps to ensure the required accurac...