A sensor for detecting oxidizable gases may comprise a catalytically inactive surface and a catalytically active surface on opposite sides of a sensor element and a thermal element running through the sensor element to connect the two surfaces, with a device for measuring a thermoelectric voltage between the catalytically active surface and the inactive surface as a measure of the difference in temperature and therefore the gas concentration. The sensor may include a hot plate mounted on a base carrier by means of narrow arms, wherein the thermal element includes at least one via extending through the hot plate and connecting the two surfaces to one another, and in the region of which the thermoelectric voltage is measured.