The invention relates to a condenser for an air conditioning system, especially an air conditioning system of a vehicle, said condenser comprising a gill block and laterally arranged headers, the gill block comprising horizontal pipes, a condensing section and a supercooling section arranged above the condensing section. Said condenser also comprises a collector (5) arranged parallel to one of the headers and receiving a drier (16), a filter (18), a downpipe (15) and a rising pipe. The collector (5) is connected to the condensing section by means of a first overflow opening (8) and to the supercooling section by means of a second overflow opening (9) in such a way that a coolant can circulate. The downpipe (15) communicates with the first overflow opening (8), on the inlet side, by means of an inflow chamber (10) arranged in the collector (5).