Although her parents thought of a career as a pharmacist, Crespin joins the Paris Opera. The woman from Marseille vanquishes with her singing: she captivates Wieland Wagner who hires her at Bayreuth and Karajan who takes her on for Salzburg. Everywhere she goes she is a superb: Marschallin in the Cavalier of the Rose by Richard Strauss, and a Carmen of great class, and all the while she defends the Berlozian colours everywhere in the world: her Summer Nights, namely, is an absolute reference.

We see her in 1965 during a recital in Paris, where she has an appointment with Berlioz: with Marguerite from The Damnation of Faust, The Spectre of the Rose, Summer Nights and Didon in the Trojans, she easily convinces us that it is no coincidence that he became her favourite composer. In spite of her fondness for the stage and great roles, she doesn't neglect the repertoire of melody and lied, to which she dedicates a great deal of her activities after being appointed as a teacher at the Conservatoire de Paris in 1976.

But before that, she already dedicated the warm tone of her voice and her wonderful diction to Le Paon by Ravel which she sings in 1972 accompanied by Janine Reiss then two lieder by Schumann and Schubert, this time with Christian Ivaldi. Back to French melody, in 1964, with Fauré (Soir) and Duparc (La Vie antérieure), and to conclude, a slumming note with Les gars qui vont à la fête by her friend and accomplice Francis Poulenc.