We have combined the Planck-HFI and IRAS maps to perform an all-sky detection of the
cold submillimetre Galactic sources over the whole sky, to build the The Planck
Catalogue of Galactic Cold Clumps, counting 13188 sources. I will describe how we
proceed to build this catalogue using an original multi-frequency detection method, and
how we characterized this population of objects using new distance estimates for one
third of them. I will finally discuss the results provided by the Herschel Galactic Cold
Core follow-up Key Programme of about 350 PGCC sources, yieldings important clues about
the early phases of the star-formation.