A door comprising: - a door frame or door fixture comprising at least one abutment element; - a door leaf, which is movable from an open position in which it opens an opening delimited by said door frame or door fixture, and a closed position in which it is resting against said abutment element of said door frame or door fixture to close said opening; - at least one guillotine seat or seat provided in said door leaf or in said door frame or door fixture; - at least one sliding element or guillotine made of material having poor magnetic interaction; wherein said guillotine is slidably accommodated in said seat so as to pass from a retracted position to an extended position and vice versa along a guillotine sliding direction (X-X); - at least one first magnet with poles (N, S) aligned or parallel to said guillotine sliding direction (X-X); - said first magnet or electromagnet being arranged integral with said guillotine; - said first magnet or electromagnet exerting a magnetic action of attraction of said guillotine into said seat; - at least one second magnet or electromagnet, separated from said first magnet or electromagnet, with poles (N, S) aligned or parallel to said guillotine sliding direction (X-X); - said second magnet or electromagnet being arranged integral with said guillotine; - at least one second magnet interaction element or electromagnet, separated by said first magnet or electromagnet and by said second magnet or electromagnet, and arranged so as to interact with said second magnet or electromagnet and arranged integral with said abutment element to attract said second magnet or electromagnet to exert an action of extraction on the guillotine; - said second magnet or electromagnet being arranged so as to push said guillotine to extract it from said seat only when said second magnet or electromagnet is arranged substantially facing said second magnet interaction element or electromagnet or when said guillotine sliding direction (X-X) intercepts said second magnet interaction element or electromagnet; characterised in that said at least one first magnet or electromagnet exerts a magnetic action which is globally lower than the magnetic action globally exerted by said at least one second magnet or electromagnet. - a door frame or door fixture comprising at least one abutment element; - a door leaf, which is movable from an open position in which it opens an opening delimited by said door frame or door fixture, and a closed position in which it is resting against said abutment element of said door frame or door fixture to close said opening; - at least one guillotine seat or seat provided in said door leaf or in said door frame or door fixture; - at least one sliding element or guillotine made of material having poor magnetic interaction; wherein said guillotine is slidably accommodated in said seat so as to pass from a retracted position to an extended position and vice versa along a guillotine sliding direction (X-X); - at least one first magnet with poles (N, S) aligned or parallel to said guillotine sliding direction (X-X); - said first magnet or electromagnet being arranged integral with said guillotine; - said first magnet or electromagnet exerting a magnetic action of attraction of said guillotine into said seat; - at least one second magnet or electromagnet, separated from said first magnet or electromagnet, with poles (N, S) aligned or parallel to said guillotine sliding direction (X-X); - said second magnet or electromagnet being arranged integral with said guillotine; - at least one second magnet interaction element or electromagnet, separated by said first magnet or electromagnet and by said second magnet or electromagnet, and arranged so as to interact with said second magnet or electromagnet and arranged integral with said abutment element to attract said second magnet or electromagnet to exert an action of extraction on the guillotine; - said second magnet or electromagnet being arranged so as to push said guillotine to extract it from said seat only when said second magnet or electromagnet is arranged substantially facing said second magnet interaction element or electromagnet or when said guillotine sliding direction (X-X) intercepts said second magnet interaction element or electromagnet;