The invention proposes a process for filling a unit container with a cosmetic product from a capsule containing a dose of said cosmetic product, where said capsule comprises a tube filled with said dose of cosmetic product, where said tube extends between a first end closed by a piston slidably mounted in a cylinder and a second end forming an initially closed outlet nozzle, and where said process comprises at least a preparatory step during which the outlet nozzle of the capsule is opened and at least one step of casting in which said cosmetic product is cast into the cosmetic product container.