From the age of ten, until the outbreak of World War II, he studied with Robert Casadesus.

1 (Luis de Pablo, 1980), Envoi (Gilles Tremblay, 1982), and Modifications (Michael Jarrell, 1983).

Conductors he collaborated with included Boulez, Bour, Gielen, Leibowitz, Maderna, Marriner, Martinon, van Otterloo, Prêtre and Scherchen.

His discography includes the complete piano music of Schoenberg (Grand Prix du Disque), Debussy and Ravel and the Sonatas of Boulez, Berg and Barraqué.

Helffer taught master classes all over the world, most notably at the Salzburg Summer Academy from 1985 to 1998.