A turbomachine of bypass type comprising a nacelle defining a fan duct with an interduct. The turbomachine comprises at least one compartment created in the thickness of the interduct or of the nacelle. The compartment is separated from the fan duct by a cold wall and comprises at least one heat-sensitive element. The compartment further is equipped with a ventilation assembly comprising at least one ventilation opening made in the cold wall in order, in use, to cause air from the fan duct to enter the compartment. Each ventilation opening comprises a passive-opening system arranged in the compartment, the system comprising a flap able to move between an open position in which the flap uncovers the opening and a closing-off position in which the flap closes off the opening, and a passive-actuation device of the flap for moving the flap between the two positions.