Door, in particular a fire retardant door, which is mounted in a public space, such as a hospital or a school, comprising a frame which is provided with an upper cross-member which is substantially horizontal and two leaves, that is to say, a service leaf (2 2) and a semi-fixed leaf (2 1) which can be moved between an open position and a closed position and which are mechanically returned, respectively, towards the closed position by a door closing member which is provided with an activation arm which is subjected to the action of return springs, and a safety device which cooperates with the door closing members and which is configured to maintain the leaves in an open position during normal operation and to automatically control the mechanical closing thereof, particularly in the event of detection of a fire under the action of a signal which is transmitted by a fire panel which is independent of any other system, the safety device of the door being integrated in a profile-member which forms a band which is mounted on the upper cross-member of the frame of the door and which comprises, for each of the two leaves (2 1, 2 2), on the one hand, a fixed support which carries an electromagnet which is supplied with voltage and which is mounted on the internal portion of the band and, on the other hand, a sliding runner which is movable in horizontal translation and which is also mounted on the internal portion of the band and which is provided with an axle which projects at the external portion thereof and which is connected to the arm of the door closing member, the fixed support carrying the electromagnet also being provided with a counter-plate which is movable in horizontal translation along it and to which there is articulated a first hook which is mounted so as to be free in terms of rotation and which is maintained against the electromagnet when it is supplied with voltage, while the sliding runner is provided, on the one hand, with a second hook which is located opposite the first hook and which is engaged therein during the manual opening of the door and, on the other hand, with a plate which is mounted on the rear portion thereof, opposite the second hook, the electromagnet and the counter-plate maintaining the first hook and the second hook engaged one in the other and therefore maintaining the leaf in an open position when the electromagnet is supplied with voltage, and in the event of the current being cut off, the first hook tilting downwards so as to release the second hook and the runner which slides outwards while moving away from the fixed support which carries the electromagnet under the action of the door closing member in order to control the closing of the leaf, the safety device also comprising a selector which is constituted by a selector bar which is fixed to the inner portion of the band and which is mounted on bearings which are constructed to allow the rotation thereof about itself and which is provided at the respective ends thereof with rollers which are capable of rolling on the plate which is mounted on the rear portion of the sliding runner which is associated with the semi-fixed leaf (2 1) and of acting as an abutment for the plate which is mounted at the rear portion of the sliding runner which is associated with the service leaf (2 2) so as to ensure that, during the automatic closing, in particular in the event of detection of a fire, the semi-fixed leaf (2 1) is closed first before the service leaf (2 2) in order to prevent poor coverage, which in particular may allow the fire to pass, which door is characterised in that the band is a universal band comprising, on the one hand, a cuttable central segment and, on the other hand, two standard lateral band segments (22 1, 22 2) which correspond to the service leaf (2 2) and the semi-fixed leaf (2 1), respectively, and which each enclose the fixed support which carries the electromagnet and the sliding runner which is associated with this leaf and a plug-in end piece which is fixed to this segment at the central portion thereof which is mounted on bearings which are constructed to allow the rotation thereof about itself and which is provided at the inner end thereof with the roller and at the outer end thereof with a plug which projects outwards, these standard plug-in end pieces constituting the end portions of the selector bar.