Device for preparing a cosmetic composition, set of capsules and associated preparation process

A device for preparing a cosmetic composition, the device-comprising:

• a structure defining a housing receiving at least one capsule, the or at least one of the capsules containing at least one constituent of the cosmetic composition,
• an outlet nozzle opening at one end of the housing, configured for being fluidically connected to a receptacle or to a preform intended to form a receptacle,
• a piston movable in translation in relation to the structure in the housing, configured for perforating the or each capsule and conveying contents of each capsule to the outlet nozzle, and
• characterized in that the device further comprises a system for checking the capsule(s) in the housing, configured for determining whether the capsule(s) arranged in the housing are suitable for contributing to the preparation of the cosmetic composition and wherein the checking system comprises a plurality of spectrometry cells, aligned parallel with the longitudinal axis X-X′ and arranged facing the capsules.