The Licensed Shared Access (LSA) approach has emerged as a viable solution to provide dynamic spectrum access by allowing the primary users (incumbents) to temporarily lease the access to their spectrum to third parties (licensees). Recently, there have been proposals in Europe and USA to share radar bands (2.3 GHz in Europe, 3.5 GHz in USA) for commercial broadband use. This paper studies the problem of coexistence between MIMO-radars (incumbent) and wireless communications systems (licensee). We first present a model for the operation of the downlink wireless system coexisting with MIMO-radar that maintains correct detectability of a target in the far field. The main objective of the wireless communication system is to dynamically reuse the radar's spectrum through maximizing the throughput of the user equipment (UE) while minimizing the total probability of sensing errors at the MIMO-radar's side. To facilitate coexistence, we employ a multi-objective optimization approach using evolutionary algorithm that guarantees to satisfy the operational objectives of both the MIMO-radar and the wireless communications system. It is shown that the derived models are accurate and the multi-objective problem can be solved using a variant of the Non-dominated Sorting Genetic Algorithm II (NSGA-II), which is considered as a fast elitist multi-objective evolutionary algorithm.