She was a member of the Deutsche Oper am Rhein from 1964 to 1991, and appeared also in Paris, at the Royal Opera House in London and at festivals including Bayreuth and Glyndebourne.

Ivan A. Alexandre [fr] from Diapason summarised her performing: "A darling of the Baroque pioneers and a Mozartian at heart and in style, the soprano from Lyon was also the intimate voice of Strauss, Debussy and Messiaen.

[2] She appeared there in more than 40 productions, including leading roles such as the female title role in Gluck's Orfeo ed Euridice, Mozart's Contessa in Le nozze di Figaro and Donna Elvira in Don Giovanni, Verdi's Gilda in Rigoletto and Desdemona in Otello, Tchaikovsky's Tatjana in Eugene Onegin, and Puccini's Mimi in La Bohème and Liù in Turandot.

[4] She also appeared there in the title roles of Dvořák's Rusalka, Arabella by Richard Strauss, and Debussy's Pelléas et Mélisande, and as Antonia in Offenbach's Les contes d'Hoffmann, Marguerite in Gounod's Faust and Anne in Stravinsky's The Rake's Progress.

[10] She performed there in 1980 and 1982 as the Marschallin in Der Rosenkavalier by Richard Strauss, alongside Felicity Lott in the title role and Krisztina Laki as Sophie.

[4] Her last role on stage was Clymène in Lully's Phaëton, conducted by Marc Minkowski and directed by Karine Saporta for the opening of Lyon's Opéra Nouvel in 1993.

[1] Her repertoire included more Mozart roles, including Celia in Lucio Silla,[1] Ilia in Idomeneo,[12] and the First Lady in Die Zauberflöte,[2] She appeared with pioneers of revivals of Baroque operas, performing Clérambault's Médée and Orphée with Reinhard Goebel,[13] Lully's Armide with Philippe Herreweghe, Leclair's Circé in Scylla et Glaucus with John Eliot Gardiner, and Handel's Melissa in Amadigi di Gaula with Roger Norrington.

[1] She also appeared in works of the 20th century such as Honegger's Diane in Les aventures du roi Pausole and Poulenc's Madame Lidoine in Dialogues of the Carmelites.

[4][12] Looking at her contributions, Minkowski expressed thankfulness for her portrayals of Poppea with Harnoncourt and Ponnelle, Ilia, Aricie, and Jenůfa, for her perfect style, exemplary diction, and her both angelic and sensual lyricism.

Yakar was Fiordiligi in the first recording of the cycle of Mozart's Da Ponte operas with period instruments conducted by Harnoncourt, performed at the Drottningholm festival.