An air conditioning system (1a, 1b, 1c, 1d) of a motor vehicle with a refrigeration circuit (2a, 2b, 2c, 2d) and a coolant circuit (30, 30a, 30b, 30c), wherein - the refrigeration circuit (2a, 2b, 2c, 2d) comprises a compressor, a refrigerant-coolant heat exchanger which can be operated as condenser/gas cooler for the heat exchange between the refrigerant and the coolant of the coolant circuit (30, 30a, 30b, 30c), as well as a first refrigerant-air heat exchanger for conditioning the intake air for the passenger compartment, wherein a first expansion device is located upstream with respect to the first refrigerant-air heat exchanger in flow direction of the refrigerant, - the coolant circuit (30, 30a, 30b, 30c) comprises a conveying device, a first coolant-air heat exchanger for heating the intake air for the passenger compartment as well as the refrigerant-coolant heat exchanger, - the refrigeration circuit (2a, 2b, 2c, 2d) is formed with a second refrigerant-air heat exchanger for conditioning the intake air for the passenger compartment, wherein a second expansion device is located upstream with respect to the second refrigerant-air heat exchanger in flow direction of the refrigerant, - the coolant circuit (30, 30a, 30b, 30c) is formed with a second coolant-air heat exchanger for heating the intake air for the passenger compartment, - the first expansion device and the first refrigerant-air heat exchanger are arranged within a first flow path (12, 12d) of the refrigeration circuit (2a, 2b, 2c, 2d), and the second expansion device and the second refrigerant-air heat exchanger are arranged within a second flow path of the refrigeration circuit (2a, 2b, 2c, 2d), wherein the flow paths (12, 12d, 13) are arranged so as to enable throughflow parallel to one another, and - the first flow path (12, 12d) with the first expansion device and with the first refrigerant-air heat exchanger and the second flow path with the second expansion device and with the second refrigerant-air heat exchanger are each formed so that they extend from a branch point (15, 17) to a first opening point, characterized in that an expansion device is formed downstream with respect to the first opening point in flow direction of the refrigerant. - the refrigeration circuit (2a, 2b, 2c, 2d) comprises a compressor, a refrigerant-coolant heat exchanger which can be operated as condenser/gas cooler for the heat exchange between the refrigerant and the coolant of the coolant circuit (30, 30a, 30b, 30c), as well as a first refrigerant-air heat exchanger for conditioning the intake air for the passenger compartment, wherein a first expansion device is located upstream with respect to the first refrigerant-air heat exchanger in flow direction of the refrigerant, - the coolant circuit (30, 30a, 30b, 30c) comprises a conveying device, a first coolant-air heat exchanger for heating the intake air for the passenger compartment as well as the refrigerant-coolant heat exchanger, - the refrigeration circuit (2a, 2b, 2c, 2d) is formed with a second refrigerant-air heat exchanger for conditioning the intake air for the passenger compartment, wherein a second expansion device is located upstream with respect to the second refrigerant-air heat exchanger in flow direction of the refrigerant, - the coolant circuit (30, 30a, 30b, 30c) is formed with a second coolant-air heat exchanger for heating the intake air for the passenger compartment, - the first expansion device and the first refrigerant-air heat exchanger are arranged within a first flow path (12, 12d) of the refrigeration circuit (2a, 2b, 2c, 2d), and the second expansion device and the second refrigerant-air heat exchanger are arranged within a second flow path of the refrigeration circuit (2a, 2b, 2c, 2d), wherein the flow paths (12, 12d, 13) are arranged so as to enable throughflow parallel to one another, and - the first flow path (12, 12d) with the first expansion device and with the first refrigerant-air heat exchanger and the second flow path with the second expansion device and with the second refrigerant-air heat exchanger are each formed so that they extend from a branch point (15, 17) to a first opening point,