Clutch mechanism designed to be installed between a motor and a transmission of a vehicle, said clutch mechanism comprising: - a clutch (100, 200) in rotation about an axis of rotation; - a actuating system designed to engage or disengage the clutch (100, 200), said actuating system comprising: ∘ a control chamber designed to receive a pressurized fluid; ∘ a balancing chamber bounded in part by a piston (105, 205), the piston (105, 205) being axially movable and radially bounding the control chamber toward the outside by an axial extension span (1053, 2053), said piston (105, 205) extending radially to the outside from said control chamber in order to engage or disengage the clutch (100, 200) under the effect of the pressurized fluid contained in the control chamber; and bounded radially toward the inside by a portion of the support hub of the clutch mechanism; ∘ an elastic return device designed to generate a force opposing a piston (105, 205) placed in movement by an actuating system of a clutch of the clutch mechanism, said elastic return device comprising: - a first annular piece designed to bear against a support face of the clutch mechanism; - a second annular piece designed to bear against the piston (105, 205) of the clutch mechanism; - a plurality of elastic elements extending between the first annular piece and the second annular piece; the second annular piece comprises at its internal peripheral end a gasket, and the second annular piece bears against a face of the piston (105, 205) oriented axially opposite the plurality of elastic elements, said elastic return device being housed in the balancing chamber and extending between the piston (105, 205) and a lateral face of the balancing chamber, characterised in that the gasket of the elastic return device is simultaneously bearing radially against the support hub and bearing axially against the piston (105, 205). - a clutch (100, 200) in rotation about an axis of rotation; - a actuating system designed to engage or disengage the clutch (100, 200), said actuating system comprising: ∘ a control chamber designed to receive a pressurized fluid; ∘ a balancing chamber bounded in part by a piston (105, 205), the piston (105, 205) being axially movable and radially bounding the control chamber toward the outside by an axial extension span (1053, 2053), said piston (105, 205) extending radially to the outside from said control chamber in order to engage or disengage the clutch (100, 200) under the effect of the pressurized fluid contained in the control chamber; and bounded radially toward the inside by a portion of the support hub of the clutch mechanism; ∘ an elastic return device designed to generate a force opposing a piston (105, 205) placed in movement by an actuating system of a clutch of the clutch mechanism, said elastic return device comprising: - a first annular piece designed to bear against a support face of the clutch mechanism; - a second annular piece designed to bear against the piston (105, 205) of the clutch mechanism; - a plurality of elastic elements extending between the first annular piece and the second annular piece; the second annular piece comprises at its internal peripheral end a gasket, and the second annular piece bears against a face of the piston (105, 205) oriented axially opposite the plurality of elastic elements, said elastic return device being housed in the balancing chamber and extending between the piston (105, 205) and a lateral face of the balancing chamber, characterised in that the gasket of the elastic return device is simultaneously bearing radially against the support hub and bearing axially against the piston (105, 205). ∘ a control chamber designed to receive a pressurized fluid; ∘ a balancing chamber bounded in part by a piston (105, 205), the piston (105, 205) being axially movable and radially bounding the control chamber toward the outside by an axial extension span (1053, 2053), said piston (105, 205) extending radially to the outside from said control chamber in order to engage or disengage the clutch (100, 200) under the effect of the pressurized fluid contained in the control chamber; and bounded radially toward the inside by a portion of the support hub of the clutch mechanism; ∘ an elastic return device designed to generate a force opposing a piston (105, 205) placed in movement by an actuating system of a clutch of the clutch mechanism, said elastic return device comprising: - a first annular piece designed to bear against a support face of the clutch mechanism; - a second annular piece designed to bear against the piston (105, 205) of the clutch mechanism; - a plurality of elastic elements extending between the first annular piece and the second annular piece; the second annular piece comprises at its internal peripheral end a gasket, and the second annular piece bears against a face of the piston (105, 205) oriented axially opposite the plurality of elastic elements, said elastic return device being housed in the balancing chamber and extending between the piston (105, 205) and a lateral face of the balancing chamber, characterised in that the gasket of the elastic return device is simultaneously bearing radially against the support hub and bearing axially against the piston (105, 205). - a first annular piece designed to bear against a support face of the clutch mechanism; - a second annular piece designed to bear against the piston (105, 205) of the clutch mechanism; - a plurality of elastic elements extending between the first annular piece and the second annular piece;