Abstract: Apparatus for controlling the opening of a door that is held in its closed position in a partition by door-blocking. The apparatus comprises a section bar support of length at least substantially equal to the height of the door, and fixed to the door or to the partition in a position such that it has a first end located at one of the top and bottom ends of the door or of the partition. The support is fitted with power supply and with data transmission comprising at least two conductors which extend substantially to said first end so as to be connected to conductors situated in the vicinity of the end of the door or the partition at which said first end is located.