The invention relates to a heat exchanger with a first fluid inlet and a first fluid outlet. A first flow path is provided between the first fluid inlet and the first fluid outlet, said flow path being formed by a number N of sub-flow paths which are arranged parallel to one another and through which a first fluid flows serially one after the other; each sub-flow path is made of a plurality of tubes which are arranged parallel to one another and through which the first fluid flows in a parallel manner; and a second fluid flows around the tubes, wherein N is greater than or equal to 3.