The injection assembly (2) includes a prefilled injection device (3), such as a syringe, provided with a coupling tip (16), for example of the Luer-Lock type, and a protection device (4) comprising a protective portion (23) removably mounted on the coupling tip (16), a supporting portion (30) connected to the protective portion (23), and an injecting element (34) removably mounted on the supporting portion (30) in a storage position. The injecting element (34) comprising an injection needle (35) and a connecting tip (36) fluidly connected to the injection needle (35), the connecting tip (36) being adapted to be mounted on the coupling tip (16) of the injection device (3) in a position of use of the injecting element (34). The injecting element (34) and the supporting portion (30) are arranged in such a way that, in the position of storage of the injecting element (34), the connecting tip (36) is accessible to cooperate with the coupling tip (16).
