Abstract: This heat exchanger can include parallel plates which define liquid-refrigerant passages following a longitudinal direction, and—fins extending in each passage in a lateral direction orthogonal to the longitudinal direction, each fin having orifices for the flow of the liquid refrigerant. At least one lower portion of at least one fin defines, with the plate secured to this lower portion, a distribution channel for channeling the liquid refrigerant in the lateral direction. The orifices in said at least one fin are formed by overflow openings in the upper portion. The liquid refrigerant flows through the overflow openings when the or each distribution channel is full of liquid refrigerant.