Unit comprising: - a cooktop having an extraction opening, - an extractor hood integrated under the cooktop and having an electric motor that actuates an extraction system to extract the air from the extraction opening, and - a filter arranged in said extraction opening, wherein said filter comprises: - a first filtering element - a second filtering element - a spacer made of an electrically insulating material and suitable for letting the air pass through, it being arranged between the first filtering element and the second filtering element characterized in that the first filtering element and second filtering element are made of electrically conductive material, wherein further the spacer is so arranged as to electrically isolate the first filtering element from the second filtering element, wherein said unit further comprises: - detection means electrically connected to the first filtering element and to the second filtering element to detect an electrical connection between the first filtering element and the second filtering element, and - control means connected to the detection means and configured to send a control signal to the electric motor of the extractor hood to stop the electric motor when the detection means detect an electrical connection between the first filtering element and the second filtering element. - a cooktop having an extraction opening, - an extractor hood integrated under the cooktop and having an electric motor that actuates an extraction system to extract the air from the extraction opening, and - a filter arranged in said extraction opening, wherein said filter comprises: - a first filtering element - a second filtering element - a spacer made of an electrically insulating material and suitable for letting the air pass through, it being arranged between the first filtering element and the second filtering element characterized in that the first filtering element and second filtering element are made of electrically conductive material, wherein further the spacer is so arranged as to electrically isolate the first filtering element from the second filtering element, - a first filtering element - a second filtering element - a spacer made of an electrically insulating material and suitable for letting the air pass through, it being arranged between the first filtering element and the second filtering element characterized in that the first filtering element and second filtering element are made of electrically conductive material, wherein further the spacer is so arranged as to electrically isolate the first filtering element from the second filtering element, wherein said unit further comprises: - detection means electrically connected to the first filtering element and to the second filtering element to detect an electrical connection between the first filtering element and the second filtering element, and - control means connected to the detection means and configured to send a control signal to the electric motor of the extractor hood to stop the electric motor when the detection means detect an electrical connection between the first filtering element and the second filtering element. - detection means electrically connected to the first filtering element and to the second filtering element to detect an electrical connection between the first filtering element and the second filtering element, and - control means connected to the detection means and configured to send a control signal to the electric motor of the extractor hood to stop the electric motor when the detection means detect an electrical connection between the first filtering element and the second filtering element.