A nacelle for use in an aircraft having a turbojet engine (the turbojet engine including a fan casing and a suspension pylon) includes a D-shaped structure downstream section embedding a thrust reverser device. The D-shaped structure downstream section includes a movable cascades vane. The D-shaped structure downstream section also includes two D-shaped half-structures each having an outer half-cowl movable in translation along a longitudinal axis, a connector between the cascades vane and the outer half-cowl, a twelve o'clock half-bifurcation, an inner half-structure defining an inner portion of the annular flow path, and a twelve o'clock half-beam mounted on the twelve o'clock half-bifurcation articulated on the pylon. The nacelle further includes an axial retention device of the downstream section of the nacelle, relative to the turbojet engine, configured to provide a connection defining an axial retention between the twelve o'clock half-beam and a fixed element of the fan casing.