A method of starting a machine comprising a plurality of modules, each module having a standard run-up time until optimum operating conditions are obtained. The method includes acquiring for each module of an initial state at a time T0 and a run-up time to reach the optimum operating conditions from the time T0. The method also includes identifying a slow module having the longest run-up time and determining a time T1 of optimum operation, following run-up, at which said slow module has its optimum operating conditions. For each module (6) other than the slow module (6), the method establishes a starting or run-up time set point for which its optimum operating conditions are reached only at the time T1 or in the immediate vicinity of the time T1.