Plant for washing fumes from suspended particles and for recovering thermal energy from fumes, comprising: a first stage and a second stage for washing fumes, a first tank, a second tank and a third tank, arranged to communicate water from one to another in cascaded fashion, wherein the first stage comprises: an inlet for the fumes and an outlet for the fumes toward the second stage, water jets forming water curtains, a tortuous, obligated path for the fumes that forces them to cross the water curtains, a conduit for water heated by the fumes towards the first tank, and the second stage comprises: an inlet for the fumes from the first stage and an output for the fumes, a tortuous path (68d, 68u) for the fumes, water jets to spray water into the tortuous path, a conduit for water heated by the fumes towards the second tank, wherein the first and second tanks each comprise a heat exchanger, the heat exchangers (26, 28) belonging to a same flowing-water circuit which enters first into the second tank and then in the first one; and the second tank comprises an outlet for fumes toward the second stage and the third tank comprises: a tortuous path (140s, 140d) for a water coming from the second tank, the tortuous path comprising means for sifting the water flow and an outlet for the water flow. a first stage and a second stage for washing fumes, a first tank, a second tank and a third tank, arranged to communicate water from one to another in cascaded fashion, wherein the first stage comprises: an inlet for the fumes and an outlet for the fumes toward the second stage, water jets forming water curtains, a tortuous, obligated path for the fumes that forces them to cross the water curtains, a conduit for water heated by the fumes towards the first tank, and the second stage comprises: an inlet for the fumes from the first stage and an output for the fumes, a tortuous path (68d, 68u) for the fumes, water jets to spray water into the tortuous path, a conduit for water heated by the fumes towards the second tank, wherein the first and second tanks each comprise a heat exchanger, the heat exchangers (26, 28) belonging to a same flowing-water circuit which enters first into the second tank and then in the first one; and the second tank comprises an outlet for fumes toward the second stage and the third tank comprises: a tortuous path (140s, 140d) for a water coming from the second tank, the tortuous path comprising means for sifting the water flow and an outlet for the water flow. an inlet for the fumes and an outlet for the fumes toward the second stage, water jets forming water curtains, a tortuous, obligated path for the fumes that forces them to cross the water curtains, a conduit for water heated by the fumes towards the first tank, and the second stage comprises: an inlet for the fumes from the first stage and an output for the fumes, a tortuous path (68d, 68u) for the fumes, water jets to spray water into the tortuous path, a conduit for water heated by the fumes towards the second tank, wherein the first and second tanks each comprise a heat exchanger, the heat exchangers (26, 28) belonging to a same flowing-water circuit which enters first into the second tank and then in the first one; and the second tank comprises an outlet for fumes toward the second stage and the third tank comprises: a tortuous path (140s, 140d) for a water coming from the second tank, the tortuous path comprising means for sifting the water flow and an outlet for the water flow. an inlet for the fumes from the first stage and an output for the fumes, a tortuous path (68d, 68u) for the fumes, water jets to spray water into the tortuous path, a conduit for water heated by the fumes towards the second tank, wherein the first and second tanks each comprise a heat exchanger, the heat exchangers (26, 28) belonging to a same flowing-water circuit which enters first into the second tank and then in the first one; and the second tank comprises an outlet for fumes toward the second stage and the third tank comprises: a tortuous path (140s, 140d) for a water coming from the second tank, the tortuous path comprising means for sifting the water flow and an outlet for the water flow. a tortuous path (140s, 140d) for a water coming from the second tank, the tortuous path comprising means for sifting the water flow and an outlet for the water flow.