Bathori originally studied piano and planned for a career as concert pianist but soon turned to singing, making her professional debut sometime in 1898 at the small Théâtre de la Bodinière in the rue Saint-Lazare in a concert to honor the poet Paul Verlaine. That same year, her debut in the grands concerts began when she appeared at the Concerts du Conservatoire followed by performances in Gabriel Fauré's La Naissance de Vénus and Camille Saint-Saëns' Messe de Requiem. During the season 1899 - 1900 she made her mezzo-soprano operatic debut at Nantes.

In the early 1900s, Bathori began studying with Pierre-Emile Engel, whom she married in 1908. In 1917, she became the director of the Théâtre du Vieux-Colombier. After the war she sang at La Scala and in other major centres across Europe. During the time of Les Six in the early 1920s she played a large role in the propagation of the new music of this period especially by some of the members of the famous Les Six. On January 31, 1920 she gave the first performance of Louis Durey's Printemps au fond de la mer. She would give the first performances of many works by other contemporary French composers.

In the 1930s she sang in the Teatro Colón in Buenos Aires, Argentina. During the German occupation of France during World War II she would make Buenos Aires her home. After her return to France she taught and coached a number of young singers. Although age put an end to her own concert career, she occasionally appeared in public and on recordings as accompanist.