A great-niece of the French author Victor Hugo and a niece of the composer Lucien Laroche, Ostermeyer was born in Rang-du-Fliers, Pas-de-Calais.

At the insistence of her mother, she began learning piano at the age of 4, and at 14 she left her family's home in Tunisia to attend the Conservatoire de Paris.

[2] After the outbreak of World War II, she moved back to Tunisia where she performed a weekly half-hour piano recital on Radio Tunis.

Her athletic prowess damaged her reputation as a concert pianist, however, and she even avoided playing anything composed by Franz Liszt for six years because she considered him too "sportif".

[2] She toured for fifteen years before personal commitments, including the death of her husband, led her to take a teaching job, a post she held until her retirement in the early 1980s.