An injection assembly, including: - a prefilled injection device comprising a coupling tip, the coupling tip including a tubular coupling part intended for the passage of a fluid, - an obturator arranged for obturating the free end of the coupling part of the coupling tip, the obturator being connected by a breakable area to the free end of the coupling part, and - a protection device comprising: - a one-piece body including: - a protective portion removably mounted on the coupling tip of the injection device so as to cover and protect at least partially said coupling tip, - a coupling portion connected to the protective portion and including a coupling housing configured to cooperate with the obturator, and - a supporting portion connected to the coupling portion, and - an injecting element removably mounted on the supporting portion in a storage position, the injecting element comprising an injection needle and a connecting tip fluidly connected to the injection needle, the connecting tip being adapted to be mounted on the coupling tip of the injection device in a position of use of the injecting element, the injecting element and the supporting portion being arranged in such a way that, in the storage position of the injecting element, the connecting tip is accessible to cooperate with the coupling tip. - a prefilled injection device comprising a coupling tip, the coupling tip including a tubular coupling part intended for the passage of a fluid, - an obturator arranged for obturating the free end of the coupling part of the coupling tip, the obturator being connected by a breakable area to the free end of the coupling part, and - a protection device comprising: - a one-piece body including: - a protective portion removably mounted on the coupling tip of the injection device so as to cover and protect at least partially said coupling tip, - a coupling portion connected to the protective portion and including a coupling housing configured to cooperate with the obturator, and - a supporting portion connected to the coupling portion, and - an injecting element removably mounted on the supporting portion in a storage position, the injecting element comprising an injection needle and a connecting tip fluidly connected to the injection needle, the connecting tip being adapted to be mounted on the coupling tip of the injection device in a position of use of the injecting element, the injecting element and the supporting portion being arranged in such a way that, in the storage position of the injecting element, the connecting tip is accessible to cooperate with the coupling tip. - a one-piece body including: - a protective portion removably mounted on the coupling tip of the injection device so as to cover and protect at least partially said coupling tip, - a coupling portion connected to the protective portion and including a coupling housing configured to cooperate with the obturator, and - a supporting portion connected to the coupling portion, and - a protective portion removably mounted on the coupling tip of the injection device so as to cover and protect at least partially said coupling tip, - a coupling portion connected to the protective portion and including a coupling housing configured to cooperate with the obturator, and - a supporting portion connected to the coupling portion, and - an injecting element removably mounted on the supporting portion in a storage position, the injecting element comprising an injection needle and a connecting tip fluidly connected to the injection needle, the connecting tip being adapted to be mounted on the coupling tip of the injection device in a position of use of the injecting element, the injecting element and the supporting portion being arranged in such a way that, in the storage position of the injecting element, the connecting tip is accessible to cooperate with the coupling tip.