Pré-publication, Document de travail: We study here whether and when a social movement can turn into a successful revolution and modify the production system. To do so, the dynamics of social unrest is de_ned as a function of the number of discriminated workers, and their organizational skills, wage inequalities, and retaliation. Then, taking the evolution of social unrest into account, we obtain the optimal time for a revolution as the moment which maximizes discriminated workers' lifetime welfare. It is proven that if unrest increases with time and if a revolution does improve the discriminated's welfare, then a revolution arises independently of the initial state and the characteristics of the economy. Whenever the gains are high enough, then a revolution arises immediately. Worth noting, we show that even if social movement loses momentum, a revolution arises if the initial mass of discontent is sizeable or the system is so repressive that it becomes necessary to revolt.