The rear assembly (10; 110; 150) according to the invention comprises at least one lateral lining (18), intended to laterally delimit a motor vehicle trunk (12).It comprises a mechanism (22) for guiding the rotation of a tray (20) for supporting objects around a transverse axis (A-A′), relative to the lateral lining (18).For each lateral lining (18), the guide mechanism (22) comprises an insertion member (60) for at least one edge (42, 46) of the tray, the insertion member (60) being rotatably mounted around the transverse axis (A-A′) on the lateral lining (18).