The HESS international collaboration, to which CNRS and CEA contribute, has published the results of fifteen years of gamma ray observations of the Milky Way. Its telescopes installed in Namibia have studied populations of pulsar wind nebulae and supernova remnants, as well as microquasars, never before detected in gamma rays. These studies are supplemented by precise measurements such as those of the diffuse emission at the center of our Galaxy. The entire set of data will henceforth serve as a reference for the international scientific community. Fourteen articles, making up the largest ever set of scientific results in this field, are published on April 9, 2018 in a special issue of the journal Astronomy & Astrophysics.