Assembly intended in particular to be arranged in a cockpit of an aircraft, said assembly comprising a respiratory mask and a stowage device, wherein: the respiratory mask has a face cover and a harness, the stowage device comprises a base and a platform, the platform is adapted to receive the respiratory mask in a stowage position where the harness forms a loop extending around the platform, the platform comprises a main element movable relative to the base between a retracted position and a protruding position, and the platform further comprises auxiliary elements, the auxiliary elements movable with respect to the main element between a flattened configuration and an expanded configuration of the platform.