A method regulating flatness of a metal strip at a roll housing output including at least one dynamic flatness actuator. A rolling process characterizes flatness of the strip by measuring a quantity D in n points distributed across the strip width, from n measurements of the quantity D. Then, using an action model of flatness regulation and an optimizing method, an overall setpoint including at least one elementary setpoint is determined for the dynamic actuator, such that a calculated flatness residual defect criterion is minimal, and executing the overall setpoint. The action model on the flatness used for determining the overall setpoint includes, for the dynamic actuator, as many submodels as there are points for measuring the quantity D characteristic of flatness, each submodel enabling the effect of the dynamic actuator on the quantity D to be calculated at the corresponding point when a setpoint is applied thereto.