Kaas is one of the most successful French-speaking singers in the world. Stylistically her music is not classical chanson, but is closer to a mixture of pop music, jazz and chanson.

Since the appearance of her debut album Mademoiselle chante... in 1988 Kaas has sold over 16 million records worldwide. She had her greatest success in, e. g., Germany, Switzerland, Belgium, Canada, Russia, Finland, and Korea with her third album Je te dis vous. Kaas is almost constantly on tour internationally. In 2002 Kaas had her film debut in And now... Ladies and Gentlemen beside Jeremy Irons. Kaas is currently on "Kabaret" world tour since the end of 2008. Kaas represented France in the Eurovision Song Contest 2009 in Moscow, Russia and finished in 8th place.