Abstract: Device for the selective detection of benzene gas, which comprises, on a base substrate, a combination of at least one functionalized multi- or single-wall carbon nanotube sensor decorated with rhodium clusters, and at least one functionalized multi- or single-wall carbon nanotube sensor decorated with metal clusters selected from gold, palladium, nickel and titanium, and/or undecorated, where said substrate additionally comprises means for measuring the variation in the resistance of said sensors. The device is useful at ambient temperature in the presence or absence of oxygen and easy to handle. It also relates to a method for the manufacturing thereof and for detecting the gas in the chemical industry, the petrochemical industry, petrol stations, or household, aeronautical or research applications.