Abstract: A heating, ventilation and/or air-conditioning device for a motor vehicle, with a housing which includes a first duct for a first air stream, a second duct for a second air stream, a partition placed inside the housing so as to separate the ducts, a first heat exchanger arranged in the ducts, said heat exchanger being common to the two ducts, a second heat exchanger which is located downstream of the first heat exchanger and is arranged within a single duct, a first flap located downstream of the second heat exchanger, an air stream guide wall which is arranged inside the first duct, downstream of the first heat exchanger, and directs the first air stream in the direction of the first flap. The housing includes a space between the air stream guide wall and the first flap so that the first flap will not abut against the air stream guide wall.