Abstract: A fireplace is provided, in which a flame can be lit. The fireplace including a warning system, which includes a proximity sensor to detect the presence of object within an active volume, the volume surrounds at least a portion of the fireplace. The system also includes an alarm device to emit an alarm signal, a clock to calculate a time elapsed since the switching off of the fireplace, and a processing unit receiving as input data from the clock and the proximity sensor, and outputting command signals to the alarm device. The alarm device is activated by the processing unit to generate an alarm signal when an object is detected by the proximity sensor as entering the active volume and the fireplace has been switched off since no later than a first pre-defined time interval. Also provided is a method for warning when an object enters the active volume of a fireplace.