Abstract: A first door closer unit and a first swing arm close a first door leaf of a pair of door leaves arid a second door closer unit and a second swing arm close the second door leaf of the pair. A guide rail supported by a door frame guides the distal ends of the swing arms. A closure sequence controller includes a control member in the guide rail between the distal ends of the swing arms and movable against the force of a spring, a support element stationarily supported by the guide rail, and a movable blocking member. The closure sequence controller is arranged in cooperation with the distal ends of the swing arms at the end phase of the closing movement of the door leaves so that the blocking member prevents movement in the guide rail of the distal end of the second swing arm until the distal end of the first swing arm acts on the blocking member through the control member go that the blocking member allows closing of the second door leaf.