Clemence started acting around the age of 14. She has since then appeared in French films. Her latest project is Harry Potter and the Goblet of Fire. She has also appeared in a mini-series, Gunpowder, Treason & Plot, where she is playing the role of Mary, who is the Queen of Scots.
She got into acting because her father is a theatre director and actor. She fell off of a horse at age seven, and did not ride one again until she was 20.