Since 2010 particle physicists and geoscientists have been collaborating within the ToMuVol project for developing density imaging of volcanoes with atmospheric muons. They have initiated experiences on the Puy de Dôme, a lava-dome located in a small field of quaternary monogenetic volcanoes, Chaîne des Puys in the centre of France. This volcano has a rather simple topography and an appropriate size for applying muon imaging and for comparing this method to standard geophysical survey techniques. Also its inner structure is complex enough for testing the performances and resolution of the different techniques. The Puy de Dôme has been studied for many years. However, recently acquired geophysical data combined with preliminary muon imaging results allowed to refine the structural model of the volcano. The Puy de Dôme close environment offers facilities for housing detectors and it is not far from the Clermont-Ferrand University. These conditions make Puy de Dôme a good candidate for a reference test site. It has already attracted other European groups involved in muon imaging research.