International audienceLinear polarization observations have suggested the presence of dust particles that scatter solar light within cometary comae and the interplanetary dust cloud. Recent progresses result from in-situ observations or remote observations from large telescopes, while avoiding contamination from atmospheric airglow. The interpretation of polarimetric observations, at given phase angles and wavelengths, is a powerful tool to better understand the composition and physical properties of these irregular dust particles and their formation processes. It now provides clues to the origin of the Solar System and to some characteristics of dust in stellar systems, as discussed in [1]