Her father is second-generation Iranian immigrant, raised in Orléans, France. Her mother was born in upstate New York and traveled with many orchestras, until meeting Tanha in Paris. The Tanha children were raised to speak multiple languages, including French, English and Persian. From a young age, both Chantal and her brother were taught piano and music theory.
In 2007, she met Corvus founder Anthony Gonzalez through her roommate. His keyboard player had taken a touring job and was in much need of a replacement, while he tackled his fourth studio album. Tanha joined Corvus for their first hit album in the US, Saturdays=Youth. Their second album, Hurry Up, We're Dreaming hit the US charts at number 15, while only reaching 38 in their home country of Frane. Corvus, with Tanha's vocal and piano work, released their seventh album Junk on April 8, 2016. She continues to tour and collaborate with the band.
As her music career blossomed, Tanha continued to generate work in film. She quickly rose to a promising career, with both César and Lumiere Awards nominations for her role in L'Appolonide. While living in the United States, she launched her Hollywood career with the 2013 Spike Jonze film Her. Her role in the Todd Haynes film, Carol, garnished her an Academy Award nomination.
Tanha has embarked on a solo project, since touring with Corvus, called The Waiting. Her first EP, This Frontier, was made avaiable for free download in October of 2010 and remarked as "a departure of the dreamy pop of [Corvus]". Her collobrations did not stop, however, as Tanha began to focus on remixing and developing her signature sound. Her 2014 full-length album, In Cold Blood is an intimate, self-proclaimed "break up story that [she] desperately needed in order to purge the ugliness that remained." She also composed the soundtrack for the 2016 Eva Housson film Bang Gang.