Apparatus for natural ventilation of a room, said apparatus comprising: - a room delimited by walls, - at least one door or one window installed in one of the room walls and comprises an opening frame produced from profiles (30a, 30b1, 30b2) supporting at least one glass panel, which opening frame is mounted so as to move in a fixed stationary frame formed by profiles (31a, 31b) surrounding said opening frame, - a ventilation passage which communicates between the outside of the room and the inside of the room in such a way as to allow natural ventilation between the outside and inside of said room, - a noise absorber capable of attenuating sound waves propagating in the ventilation passage, said attenuation being realized by the generation of a counter-noise which is superimposed on said sound waves, - the opening frame is mounted movably in the stationary frame between a closed position wherein a first profile (30b1) of the opening frame is attached to the first corresponding profile (31b1) of the stationary frame and an open position wherein the first profile (30b1) of the opening frame is separated from the first profile (31b1) of the stationary frame, wherein, - in an intermediate open position of the opening frame, the first profile (30b1) of the opening frame is separated from the first profile (31b1) of the stationary frame by a predetermined distance, - the ventilation passage is delimited by the space separating the first profile (30b1) of the opening frame from the first profile (31b1) of the stationary frame when said opening frame is in the intermediate open position, - the noise absorber is directly installed in the first profile (30b1) of the opening frame and/or in the first profile (31b1) of the stationary frame, - when the opening frame is in the closed position, the first profiles (30b1, 31b1) are attached together in such a way that the ventilation passage is hermetically closed, with any ventilation between the inside and outside of the room by said ventilation passage being prevented. - a room delimited by walls, - at least one door or one window installed in one of the room walls and comprises an opening frame produced from profiles (30a, 30b1, 30b2) supporting at least one glass panel, which opening frame is mounted so as to move in a fixed stationary frame formed by profiles (31a, 31b) surrounding said opening frame, - a ventilation passage which communicates between the outside of the room and the inside of the room in such a way as to allow natural ventilation between the outside and inside of said room, - a noise absorber capable of attenuating sound waves propagating in the ventilation passage, said attenuation being realized by the generation of a counter-noise which is superimposed on said sound waves, - the opening frame is mounted movably in the stationary frame between a closed position wherein a first profile (30b1) of the opening frame is attached to the first corresponding profile (31b1) of the stationary frame and an open position wherein the first profile (30b1) of the opening frame is separated from the first profile (31b1) of the stationary frame, wherein, - in an intermediate open position of the opening frame, the first profile (30b1) of the opening frame is separated from the first profile (31b1) of the stationary frame by a predetermined distance, - the ventilation passage is delimited by the space separating the first profile (30b1) of the opening frame from the first profile (31b1) of the stationary frame when said opening frame is in the intermediate open position, - the noise absorber is directly installed in the first profile (30b1) of the opening frame and/or in the first profile (31b1) of the stationary frame, - when the opening frame is in the closed position, the first profiles (30b1, 31b1) are attached together in such a way that the ventilation passage is hermetically closed, with any ventilation between the inside and outside of the room by said ventilation passage being prevented.