A resistance thermometer is provided having a measuring resistor in a form of a 0.1 to 10 μm thick structured platinum layer applied to an electrically insulated surface of a substrate and an electrically insulating coating layer covering the platinum layer. The substrate or its surface contains zirconium dioxide, which is stabilized with oxides of a trivalent and a pentavalent metal. Preferably, the trivalent metal is yttrium and the pentavalent metal is tantalum or niobium. The characteristic curve of the measuring resistor preferably conforms to DIN-IEC 751. For mass production of resistance thermometers having high and reproducible measurement accuracy, a structured platinum layer having a thickness of 0.1 to 10 μm is applied to an electrically insulating substrate having a thermal expansion coefficient in the range of 8.5 to 10.5×10−6/° K and a roughness less than 1 μm, and the structured platinum layer is covered by an electrical insulator. The resistance thermometers allow precise temperature measurement between −200° C. and +850° C., preferably as a sensor in an exhaust gas treatment system. In a substance-sensitive sensor having a circuit path structure on a substrate, the circuit path structure has an epitaxially applied base layer, and a substance-sensitive metal layer attached to the epitaxially applied base layer.