Abstract: The invention concerns a self-regulating open fireplace and more particularly a corner open fireplace, a fireplace which is open on three sides and a fireplace which is open upon one side only.In the fixed hood of the fireplace there is fitted a hinging movable hood of truncated cone shape of which, in one position, the bottom contour is in contact with the bottom contour of the fixed hood, and in a hinged position, a continuous passage is formed between the two hoods so as to create an air curtain in front of the open fireplace and to extract all excess smoke gasses, whereas means are provided between the movable hood and a flap valve mounted in the movable hood for adjusting the passage opening of the chimney, in view of the simultaneous control of the movable hood and of the flap valve.