A gas sensor has at least one gas sensitive layer, which has at least one surface area in which the work function is dependent upon the concentration of a target gas capable of being brought into contact with the surface zone. At least one electric potential sensor is capacitatively coupled to the surface zone over an air gap. The surface zone of the gas sensitive layer is covered with an electrically insulating coating which is inert to the target gas and which is adhesively bound to the gas sensitive layer. The coating is configured so that it is permeable to the target gas and so that when the target gas contacts the surface zone of the gas sensitive layer, it prevents or at least impedes an alteration of the bound state of atoms and/or molecules bound to the surface zone and differing from the target gas.