Example embodiments provide a device for protecting an inner space of an object against fire, including a housing provided with at least one passage opening; an aerosol-forming extinguishing element arranged in the housing and which may include a container for holding extinguishing material which can be activated at a fixed activating temperature; at least one outlet opening which can be connected to the passage opening in the housing and along which the activated extinguishing material can be carried into the inner space of the object so as to extinguish the fire; an activating element for bringing at least part of the extinguishing material to the activation temperature; at least one detection unit arranged in or close to the housing for detecting at least one physical and/or chemical parameter representative of fire in the inner space; and a control unit arranged in the housing for causing thermal activation of the extinguishing element by the activating element when a preset activation value of the detected physical and/or chemical parameter is reached. The housing may be embodied for placing in the inner space of the object.