the incentive seating module comprises : a structural frame provided with a gaiter , a frame , disposed above said structural frame and provided with an arch , whereby the structural frame exhibits planar symmetry , means for connecting the frame to the structural frame comprising a joint enabling the frame to swivel in relation to the structural frame about an axis which is perpendicular to the symmetrical plane , and a seating element joining the frame to the gaiter , made of an elastic membrane which is used to define a rest position for the frame in relation to the structural frame and to return it towards said position when a user causes it to tilt in one direction or the other .