Fluid thermal treatment installation for aircraft, said installation comprising at least one cooling system for cooling at least one member to be cooled and at least one thermal treatment system for thermal treatment of the air of a cabin of the aircraft, -) the cooling system comprising a closed circuit for circulating a fluid to be cooled between the member to be cooled and at least one heat exchanger equipped with a ventilation member, the heat exchanger being interposed on the closed circuit via an internal circuit for circulating the fluid to be cooled, and comprising a thermal exchange structure through which circulates a cooling air stream generated by the ventilation member, *) the air thermal treatment system comprising regulating means for regulating a heating air stream admitted to the cabin, and an open circuit for conveying a plurality of air streams, the open circuit comprising a first air circuit for conveying a source air stream generated by a compressor to at least one thermal treatment apparatus and a second air circuit for conveying to the cabin said heating air stream coming from the thermal treatment of the source air stream, the cooling system and the thermal treatment system comprising a group of shared members, including at least: a) said compressor generating a source air stream at moderate pressure and temperature, the compressor being an accessory compressor provided with an air inlet and driven from an engine member, b) said heat exchanger, forming cooperating means for cooling the fluid to be cooled and for heating the source air stream coming from the accessory compressor, the heating of the source air stream producing a hot air stream by withdrawing calories participating in the cooling of the thermal exchange structure characterised in that said ventilation member is a ventilator with ejection ramp generating the cooling air stream from an activation air stream, and in that the group of shared members comprises: c) a distribution valve for distributing said source air stream selectively to the ventilator with ejection ramp by forming the activation air stream and/or to the cabin by forming said heating air stream coming from the hot air stream. -) the cooling system comprising a closed circuit for circulating a fluid to be cooled between the member to be cooled and at least one heat exchanger equipped with a ventilation member, the heat exchanger being interposed on the closed circuit via an internal circuit for circulating the fluid to be cooled, and comprising a thermal exchange structure through which circulates a cooling air stream generated by the ventilation member, *) the air thermal treatment system comprising regulating means for regulating a heating air stream admitted to the cabin, and an open circuit for conveying a plurality of air streams, the open circuit comprising a first air circuit for conveying a source air stream generated by a compressor to at least one thermal treatment apparatus and a second air circuit for conveying to the cabin said heating air stream coming from the thermal treatment of the source air stream, a) said compressor generating a source air stream at moderate pressure and temperature, the compressor being an accessory compressor provided with an air inlet and driven from an engine member, b) said heat exchanger, forming cooperating means for cooling the fluid to be cooled and for heating the source air stream coming from the accessory compressor, the heating of the source air stream producing a hot air stream by withdrawing calories participating in the cooling of the thermal exchange structure c) a distribution valve for distributing said source air stream selectively to the ventilator with ejection ramp by forming the activation air stream and/or to the cabin by forming said heating air stream coming from the hot air stream.