The application concerns a compressor comprising a fixed part and a part (10) movable relative to said fixed part, aid movable part (10) being configured to follow an orbital movement around an orbit axis, said compressor further comprising at least one anti-rotation assembly (20), formed of a ring (22) and a pin (24) configured to immobilize said movable part (10) against rotation on itself during its orbital movement, said fixed part and said movable part (10) being separated at least locally by a space forming an axial clearance (J), crossed by said pin (24), said ring (22) penetrating into said space.