Katia and Marielle were born in Bayonne, on the southwest coast of France near the Spanish border (Northern Basque Country). Their father was a doctor, rugby football player and music lover. He sang in the Bordeaux Opera choir. The sisters' first teacher was their Italian mother, Ada Cecchi (a former student of Marguerite Long), who began lessons when her daughters were three and five years of age.Upon graduation in piano from the Conservatoire de Paris in 1968, the two began working on piano four hands and two pianos repertoire. They recorded their first album Les Visions de l'Amen of Olivier Messiaen under the artistic direction of the composer himself. They then undertook performance of contemporary music, performing works by Luciano Berio, Pierre Boulez, Philippe Boesmans, György Ligeti and Olivier Messiaen.