A device for detecting a failure of a filter used to clean a gas stream, in particular an exhaust gas stream, of soot particulates, including a chamber which is insertable into the gas stream to be cleaned in addition to the filter and which is at least partially closed by a filter body and has at least one opening through which gas entering the chamber through the filter body can exit the chamber, at least one gas sensor for determining the concentration of at least one component of the gas to be cleaned being arranged in the chamber, and at least one second gas sensor for determining the concentration of the at least one component of the gas to be cleaned being arranged outside the chamber.