Abstract: Heat exchanger with plates, which is configured for a heat exchange between a hot fluid and a cold fluid, comprising at least one core band (130a, 130b) arranged in order to maintain the sealing tightness, a plurality of closing bars (138) defining, with the closing plates, flow channels, characterized in that the core band (130a) arranged at a cold pass inlet and at a hot pass inlet comprises an inlet (132) for supplying hot air, and in that at least one closing bar (138) arranged in the lengthwise direction of the inlet of the cold pass comprises an inlet for said hot air and a flow circuit for said hot air in a U shape and comprising two sections, each extending over the whole length of the closing bar, a hot air outlet for expelling the hot air in the hot pass, and an intermediate section forming the base of the U.