The present disclosure relates to a seat member comprising a first shell, a second shell fixed to the first shell, and a padding covering the second shell such that the second shell is sandwiched between the first shell and the padding, the padding being configured to support a user, and a ventilation system comprising a fan and a duct, the duct being defined by the first shell and the second shell and forming an air passage placing the fan and padding in communication via holes in the second shell. The duct comprises a housing able to receive the fan, and the first shell comprises a door through which the fan can be placed in the housing, the fan having a first orifice for the passage of air between the exterior and the fan, the door having a hole located facing the first orifice.