Born in 1965, Piens holds a Masters degree in Art History from Paris I University. In the 80s, he first worked as a Gallery Assistant at the Galerie Krief, Paris, then switched in the 90s from the arts to the Hospitality Business. In 1993, he was named communication manager of Hotel Scribe, Paris, where he initiated and curated many cultural projects, most notably L’Egypte au Scribe, Exposition Pierre de Fenoyl in 1998, 24 hours Deluxe in 1999, an artistic performance with the artists Chantal Michel, Paul Armand Gette, Muntean Rosemblum and others
In 2000, Piens became Press and conference Manager of the International art fair of Paris (FIAC) and then of Paris Photo as of 2002. Since 2008, he is the artistic director and fair manager of Paris Photo.