A heat exchanger for exchanging heat between two fluids, respectively a first initially two-phase fluid and a second fluid, the heat exchanger comprising the following components: - a housing that encloses an internal cavity; - a set of channels, where each one of the channels in said set passes through the internal cavity of the housing; - an inlet collector comprising a wall with an inlet for the first initially two-phase fluid, which inlet is in fluid communication with an inlet collector chamber within the inlet collector, where both the inlet and the inlet collector chamber are symmetrical in planes of symmetry according to a first plane of symmetry and a second plane of symmetry intersecting said first plane of symmetry, the inlet collector being hermetically connected to the housing on one side of the inlet collector disposed opposite the wall with the inlet, and where the inlet collector chamber comprises first flow-rate distribution means configured to distribute a first initially two-phase fluid flow originating from the inlet evenly across the set of channels; and - an outlet collector comprising a wall with an outlet for the first initially two-phase fluid, which outlet is in fluid communication with an outlet collector chamber in the outlet collector, where said outlet collector is hermetically connected to the housing on a side of the outlet collector disposed opposite the wall with the outlet, where all inlet orifices of the set of channels are in fluid communication with the inlet collector chamber and all outlet orifices of the set of channels are in fluid communication with the outlet collector chamber, where the inlet orifices of the channels are symmetrically arranged with respect to each other according to the first plane of symmetry and the second plane of symmetry, wherein the first flow-rate distribution means consist of a single body that comprises two flow-conducting surfaces, which two flow-conducting surfaces are symmetrical with respect to each other according to the first plane of symmetry and the second plane of symmetry, and which two flow-conducting surfaces, as seen from the inlet, are inclined downward in a first direction perpendicular to the first plane of symmetry and/or in a second direction perpendicular to the second plane of symmetry, characterized in that a cross section of the first flow-rate distribution means, considered in a plane equal or parallel to the first plane of symmetry or the second plane of symmetry, comprises a substantially full figure formed by the two flow-conducting surfaces and a substantially straight base, the flow-conducting surfaces each being connected by the base at an end situated furthest away from the inlet. - a housing that encloses an internal cavity; - a set of channels, where each one of the channels in said set passes through the internal cavity of the housing; - an inlet collector comprising a wall with an inlet for the first initially two-phase fluid, which inlet is in fluid communication with an inlet collector chamber within the inlet collector, - an inlet collector comprising a wall with an inlet for the first initially two-phase fluid, which inlet is in fluid communication with an inlet collector chamber within the inlet collector, where both the inlet and the inlet collector chamber are symmetrical in planes of symmetry according to a first plane of symmetry and a second plane of symmetry intersecting said first plane of symmetry, the inlet collector being hermetically connected to the housing on one side of the inlet collector disposed opposite the wall with the inlet, and where the inlet collector chamber comprises first flow-rate distribution means configured to distribute a first initially two-phase fluid flow originating from the inlet evenly across the set of channels; and - an outlet collector comprising a wall with an outlet for the first initially two-phase fluid, which outlet is in fluid communication with an outlet collector chamber in the outlet collector, - an outlet collector comprising a wall with an outlet for the first initially two-phase fluid, which outlet is in fluid communication with an outlet collector chamber in the outlet collector, where said outlet collector is hermetically connected to the housing on a side of the outlet collector disposed opposite the wall with the outlet, where all inlet orifices of the set of channels are in fluid communication with the inlet collector chamber and all outlet orifices of the set of channels are in fluid communication with the outlet collector chamber, where the inlet orifices of the channels are symmetrically arranged with respect to each other according to the first plane of symmetry and the second plane of symmetry, wherein the first flow-rate distribution means consist of a single body that comprises two flow-conducting surfaces, which two flow-conducting surfaces are symmetrical with respect to each other according to the first plane of symmetry and the second plane of symmetry, and which two flow-conducting surfaces, as seen from the inlet, are inclined downward in a first direction perpendicular to the first plane of symmetry and/or in a second direction perpendicular to the second plane of symmetry, characterized in that a cross section of the first flow-rate distribution means, considered in a plane equal or parallel to the first plane of symmetry or the second plane of symmetry, comprises a substantially full figure formed by the two flow-conducting surfaces and a substantially straight base, the flow-conducting surfaces each being connected by the base at an end situated furthest away from the inlet.