Isabelle Geffroy, born 1 May 1980, known by the pseudonym ZAZ, is a singer from Tours, France, who blends the styles nu jazz, soul and acoustic in her music.In 2001, she started her singing career in the blues band "Fifty Fingers".

She sang in musical groups in Angoulême, especially in a jazz quintet. She became one of the four singers of Izar-Adatz (Shooting Star), a variety band which consisted of sixteen people with whom she toured for two years, especially in the Midi-Pyrenees and the Basque Country.

She worked in the studio as a chorister in Toulouse and performed with many singers including Maeso, Art Mengo, Vladimir Max, Jean-Pierre Mader and Serge Guerao.In May 2010, French magazine Telerama announced: "Rumor has swelled in recent weeks: Zaz is a sacred voice, and she will be the revelation of the summer!".

On 10 May 2010, Zaz released her first album. It contains songs written by herself ("Trop sensitible") and co-composed ("Les Passants", "Le Long de la route", "Prends garde à ta langue", "J'aime à nouveau", "Ni Oui Ni Non").

Kerredine Soltani produced the album under Play On label, and wrote and composed the hit single "Je veux". The pop singer Raphaël Haroche wrote her songs "Éblouie par la nuit", "Port Coton" and "La Fée".

In 2010, she signed a contract for her tours with Caramba and publisher Sony ATV. She was invited to many TV shows (such as Taratata or Chabada) and was featured in several programs on the radio.Zaz then toured France (Paris, La Rochelle, Montauban, Saint-Ouen, Chateauroux, Landerneau, Fécamp…), performed at the Francofolies of Montreal (Canada), Monthey (Switzerland), Brussels, Berlin, and Milan… In autumn Zaz topped the charts in Belgium, Switzerland, and Austria.

Matthieu Baligand, her manager and producer at Caramba Entertainment, explained to Liberation: "We talk a lot of her right now and people are waiting her at the turn… Despite the demand, it seems preferable to do her first tour in fifty small places which will render her credible.

Zaz is a popular, intuitive artist, who is familiar with music, who can sing, but doing a quality show is something else (…)." In November 2010, the debut album Zaz became double platinum, and she was awarded "Revelation Song" by the Academy Charles Cros.

Zaz also won the European Border Breaker Awards: she was named the French artist most played abroad in 2010. According to a survey published by L'Internaute, Zaz was the most favorite singer of the French in the 2010 ranking