Closing system for door panels comprising: - a fixed frame that defines an opening, - a first door panel connected to the fixed frame, - a second door panel connected to the first door panel, and - a mechanism connecting the first door panel to the fixed frame and the second door panel to the first door panel, in such manner that the door panels (2, 3) can go from an open position, wherein the door panels leave the opening defined by the fixed frame open, to a close position, wherein the door panels close the opening defined by the fixed frame; said mechanism comprising: - a first hinge unit that connects the first door panel to the fixed frame, - a second hinge unit that connects the second door panel to the first door panel, and - an articulated unit that connects the second door panel to the fixed frame; said articulated unit comprising: - a first plate intended to be fixed to the fixed frame, - a second plate intended to be fixed to the second door panel, and - a connective rod pivoted to the first plate by means of a first pin and to the second plate by means of a second pin; wherein the second plate of the articulated unit is fixed to an upper edge of the second door panel in such a way as to stop the second door panel against said first door, when the door panels are in open position; said second plate of the articulated unit is fixed to an upper edge of the second door panel near a lateral end of the second door panel and the first plate of the articulated unit is fixed to a crosspiece of the fixed frame in an intermediate position of said crosspiece; wherein said first hinge unit comprises an upper hinge disposed above an upper edge of the first door panel and a lower hinge disposed under a lower edge of the first door panel, characterized in that said first hinge unit, second hinge unit and articulated unit are mutually not connected; wherein said upper hinge comprises a first plate intended to be fixed to the crosspiece of the fixed frame and a second plate intended to be fixed to the upper edge of the first door panel, said plates (40, 41) of the upper hinge having an "L"-shape with a long arm and a short arm, wherein the short arms are pivoted by means of a pin. - a fixed frame that defines an opening, - a first door panel connected to the fixed frame, - a second door panel connected to the first door panel, and - a mechanism connecting the first door panel to the fixed frame and the second door panel to the first door panel, in such manner that the door panels (2, 3) can go from an open position, wherein the door panels leave the opening defined by the fixed frame open, to a close position, wherein the door panels close the opening defined by the fixed frame; said mechanism comprising: - a first hinge unit that connects the first door panel to the fixed frame, - a second hinge unit that connects the second door panel to the first door panel, and - an articulated unit that connects the second door panel to the fixed frame; - a first hinge unit that connects the first door panel to the fixed frame, - a second hinge unit that connects the second door panel to the first door panel, and - an articulated unit that connects the second door panel to the fixed frame; said articulated unit comprising: - a first plate intended to be fixed to the fixed frame, - a second plate intended to be fixed to the second door panel, and - a connective rod pivoted to the first plate by means of a first pin and to the second plate by means of a second pin; - a first plate intended to be fixed to the fixed frame, - a second plate intended to be fixed to the second door panel, and - a connective rod pivoted to the first plate by means of a first pin and to the second plate by means of a second pin; wherein the second plate of the articulated unit is fixed to an upper edge of the second door panel in such a way as to stop the second door panel against said first door, when the door panels are in open position; said second plate of the articulated unit is fixed to an upper edge of the second door panel near a lateral end of the second door panel and the first plate of the articulated unit is fixed to a crosspiece of the fixed frame in an intermediate position of said crosspiece; wherein said first hinge unit comprises an upper hinge disposed above an upper edge of the first door panel and a lower hinge disposed under a lower edge of the first door panel, characterized in that said first hinge unit, second hinge unit and articulated unit are mutually not connected; wherein said upper hinge comprises a first plate intended to be fixed to the crosspiece of the fixed frame and a second plate intended to be fixed to the upper edge of the first door panel, said plates (40, 41) of the upper hinge having an "L"-shape with a long arm and a short arm, wherein the short arms are pivoted by means of a pin.