The goal of this Master thesis is the implementation of DECASIM: a data-driven, discrete-event simulator for electric car sharing systems in Smart Cities. DECASIM is able to model car sharing demand from data coming from real car sharing systems in 25 cities, and create parametrised simulation scenarios in order to compare different fleet management strategies. The main focus of this thesis is given to charging strategies, which are critical for the correct implementation, deployment and functioning of ECS (Electric Car Sharing) systems. Input data have been collected during 2017 using the software UMAP (Urban Mobility Analysis Platform) and consist in a trace of real origin-destination bookings done by users.