Her principal biographer Gustave Bord speculates that she had run away from the school with the son of the famous merchant of shawls on the Place des Victoires, Monsieur Ternaux.

[3] For the 1832–1833 season, she appeared in secondary roles at the Monnaie under the name of Mlle Ternaux, and in 1833–1834 was heard in Lille in Rossini's operas Il barbiere di Siviglia, Tancredi, and Otello, performing in Italian.

It was during this period that she began her rivalry with the soprano Julie Dorus-Gras, who had come to Lille to sing Alice in Meyerbeer's Robert le diable.

On 23 December she sang Rachel in the Brussels's premiere of Halévy's La Juive, the success of which equaled that of Robert le diable in the same house on 10 October 1833.

She also appeared as Petit-Jacques in Rossini's La pie voleuse (The Thieving Magpie) on 14 May 1835 and as Marguerite in Hérold's Le pré aux clercs on 15 May.

[5] Stoltz finally made her debut at the Paris Opera on 25 August 1837 in La Juive, partnered not by Nourrit, with whom she would never again appear, but with his rival Gilbert Duprez.

In view of the circumstances, Donizetti decided to abandon his original project for the Opéra, Le duc d'Albe, and instead composed La favorite with the role of Léonor perfectly suited for Stoltz.