No. It's not. You've got two stories muddled up.
Back in 2006, Audrey Tautou was cast as Coco Chanel in the french film Coco avant Chanel, on which shooting is planned for later this year.
In mid 2007, Keira became the new face of Coco Mademoiselle, a fragrance intended for the younger Chanel market. A short advertising film was made, in which she was playing the part of Coco Chanel.