This article presents an optimization method using a genetic algorithm to optimize the marine current turbines arrangement in tidal farms. A semi-analytical method is adopted to minimize the negative interactions between turbines caused by wake effects. The optimization approach is applied to a tidal energy site located in the Fromveur Strait, which represents the second greatest tidal potential in France. An exclusion zone has been defined in the domain to simulate possible physical constraints. The results show that it is preferable to install a maximum number of turbines on both sides of the domain with an average longitudinal and lateral distance between turbines of 11.37 and 5.83 respectively.