She was born in Milan. Repetto designed a ballet shoe for her son, the dancer Roland Petit, at her workshop in Paris in 1947. She developed ballet flats for Brigitte Bardot in 1956 for the film And God Created Woman. They were known as Cendrillon, from the French version of Cinderella, and became popular as a fashion shoe. In 1958, she opened a boutique in Paris. Her customers included Maurice Béjart, Rudolf Nureyev, Mikhail Baryshnikov, Carolyn Carlson, the Kirov Ballet and the Folies Bergère.
She died in Paris.