Voeffray trained as a fashion designer at the Fashion Design School in Zurich and initially worked as a freelancer. In 1993 she was hired by the Theater Bern, where she became deputy head of the costume department in 1997. There she designed costumes for numerous theater and opera productions. She has also worked for the Maggio Musicale Fiorentino and the Teatro del Giglio Lucca. For many years she has worked closely with choreographer Stijn Celis on ballet productions, including Les Grands Ballets Canadiens Montréal, Cullberg Ballet, Nederlands Dans Theater, Cedar Lake Dance Company New York, Ballett der Semperoper Dresden, Aalto Ballett Essen and Ballett Staatstheater Saarbrücken. She has already designed costumes for Martin Schläpfer for the Bern Ballet. Numerous productions for ballettmainz followed, including "The Art of Fugue", "A Forest, a Lake", "3" and "Symphonies", as well as for the Ballett am Rhein, of which "A German Requiem" and "Night Surrounds" are particularly noteworthy. For Ballett am Rhein, Catherine Voeffray also collaborated with choreographer Martin Chaix and reconstructed Rei Kawakubo's costumes for Merce Cunningham's "Scenario".