Abstract: The invention relates to catalysts for the treatment of combustion gases. The catalysts include an active phase of the perovskite having the general formula: L.sub.x L'.sub.1-x M.sub.y M'.sub.z .phi..sub.1-y-z O.sub.3, wherein L is an element selected from lanthanides and rare earths, L' is an element selected from a group consisting of Sr, Ca, Ba, Ce, K, Bi, Rb or Na; M is a transition metal selected from a group consisting of Cr, Mn, Fe, Co, Ni and Cu; M' is at least one metal selected from a group consisting of Pt, Ru, Pd, Rh; .phi. is a cationic lacuna; 0<x<0.5, 0.85<y.ltoreq.1, 0.ltoreq.z<0.08 with 0.85<y+z.ltoreq.1. The catalysts of the invention are particularly useful for purifying exhaust gas from diesel engines, particularly for the removal of soot.