A system for monitoring a filter used for filtering a fluid in an aircraft engine. The system includes a pressure sensor acquiring over time a differential pressure of the fluid through the filter; a computer for computing a normalized differential pressure under reference conditions by normalizing the measured differential pressure according to conditions for exploiting the fluid; a memory for storing a predetermined reference clogging curve describing a time-dependent change of the normalized differential pressure depending on a pollutant mass injected into the filter. The computer can estimate the pollutant mass injected into the filter by projecting a current value of the normalized differential pressure onto the reference clogging curve; and can generate from the estimated pollutant mass a set of signatures defining the condition and the time-dependent change of clogging of the filter.