Metis is a,tool for simulating large-scale electric systems. By doing so, it allows to evaluate different investment strategies: is it useful or not to build a new transmission line or to invest in new wind turbine farms? More generally, Metis helps in optimizing the electric infrastructure on a European level. Metis is based on black-box optimization methods and machine learning. In collaboration with the company Artelys, Metis has been tested on real test scenario.