3D and free-viewpoint video has been moving towards solid-scene representation using meshes and point clouds. Pointcloud processing requires much less computation and the points in the cloud are minimally represented by their geometry (3D position) and color. A common point-cloud geometry compression method is the octree representation, which acts on individual frames. We present a lossless inter-frame compression method for pointcloud geometry, by reordering each octree based on previous frames prior to entropy coding. Results show that compared to the octree representation, the proposed solution offers an average rate reduction of 30%, while entropy-coding of the octree yields an average rate reduction of 24%.