Several researchers had suggested the importance of taking in account particle rearrangement for realistic analysis and modeling of solid state sintering. However evidencing and quantifying this rearrangement is a delicate task, which may require novel tools. This work investigates particle rearrangement by using in situ X ray microtomography. A spherical copper powder with a wide size distribution (0-63 μm) that possibly includes artificially created pores was sintered at the European Synchrotron Research Facilities at 1050°C. X ray microtomography provided 3D images of the microstructure at successive times of sintering with a resolution of 1.6 μm. We propose two approaches to estimate particle rearrangement. First, we compare the real displacement of particle centres all over sintering with the displacement predicted by mean field theory. Secondly we measure the rotations between triplets of contacting particles. The results obtained with both methods allow correlating particle rearrangement with various parameters as sintering advancement, porosity, coordination.