A method for assisting the manipulation of at least n graphical image processing variables by a user is provided with a control organ having a plurality of modes of activation, based on a control polygon appearing on a screen portion provided with a marker. At least each vertex of the control polygon represents a processing variable, each vertex being movable between two limit points defining a direction of action by at least one mode of activation of the control organ. A movement in this direction means a modification of the value of the variable, which is proportional to the amplitude of the movement.