A compact device for the diffusion of fragrance comprising: - a ventilation duct comprising an inlet and an outlet, and - an air flow generator, so arranged as to blow air into the ventilation duct, so that air flows in the downstream direction from the inlet to the outlet of the ventilation duct, - a mounting bracket which is arranged downstream of the air flow generator and so designed as to have a fragrance cartridge fixed thereon, so that the fragrance is in the way of the air blown, - a partition located in the ventilation duct between the air flow generator and the mounting bracket, with the condition of the partition being liable of being changed between at least: o a partitioning state and a non-partitioning state, in which the partition prevents air from flowing between a first space of the ventilation duct upstream of the partition and a second space of the ventilation duct downstream of the partition, and o a non-partitioning condition in which the partition lets air flow between the first and second spaces of the ventilation duct, and - a servo-control, between the air flow generator and the partition, so designed that the partition is in the partitioning state when the air flow generator is stopped, with the partition and the ventilation duct being made at least in part of a material inert to fragrances, which will not be permeated with a fragrance, characterized in that it comprises a switch able to start or to stop the air flow generator, with the servo-control consisting in control electronics able to modify the condition of the partition so that: - the partition leaves the partitioning state when the air flow generator is started, and - the partition reaches the partitioning state before the air flow generator is stopped. - a ventilation duct comprising an inlet and an outlet, and - an air flow generator, so arranged as to blow air into the ventilation duct, so that air flows in the downstream direction from the inlet to the outlet of the ventilation duct, - a mounting bracket which is arranged downstream of the air flow generator and so designed as to have a fragrance cartridge fixed thereon, so that the fragrance is in the way of the air blown, - a partition located in the ventilation duct between the air flow generator and the mounting bracket, with the condition of the partition being liable of being changed between at least: o a partitioning state and a non-partitioning state, in which the partition prevents air from flowing between a first space of the ventilation duct upstream of the partition and a second space of the ventilation duct downstream of the partition, and o a non-partitioning condition in which the partition lets air flow between the first and second spaces of the ventilation duct, and o a partitioning state and a non-partitioning state, in which the partition prevents air from flowing between a first space of the ventilation duct upstream of the partition and a second space of the ventilation duct downstream of the partition, and o a non-partitioning condition in which the partition lets air flow between the first and second spaces of the ventilation duct, and - a servo-control, between the air flow generator and the partition, so designed that the partition is in the partitioning state when the air flow generator is stopped, - the partition leaves the partitioning state when the air flow generator is started, and - the partition reaches the partitioning state before the air flow generator is stopped.