System diffusing the airstream blown into the vehicle passenger compartment

The invention relates to a device for distributing an air flow F inside a passenger compartment, in particular of a motor vehicle, comprising an air supply zone (2, 2A) at least part of whose distribution is carried out through a porous panel (3, 3A), constituting in particular at least part of a dashboard (4, 4A), a door panel or a roof panel, and allowing the free flow of said air flow F simultaneously in all directions of space, characterized in that a filtering member (5, 5A) is interposed between the air supply zone (2, 2A) and the porous panel (3, 3A).