Abstract: A syringe provided with a body, a piston capable of sliding in the body, and an injection device comprising a needle oriented along a longitudinal axis and a casing removably secured to the body and carrying said needle. The casing comprising a plurality of flexible tabs, each provided with a stop. The piston comprising a docking system having a housing comprising a flange configured to hold the stops of the flexible tabs in the housing in an insertion position in which the tabs are inserted into the housing, the plurality of tabs in opposing areas around the longitudinal axis. The flange comprising bearing areas configured to be in contact with corresponding tabs in the insertion position. The tabs are configured to exert an elastic pressure on corresponding bearing areas in the insertion position, and the bearing areas are dissymmetrical relative to the longitudinal axis.