The French-bred Ms. Mercier laid the 'foundation' for her profession in primping at a Parisian painting school. She eventually decided her favorite canvas was the face and traded in her paintbrush for a blush brush. The belief behind her signature 'Flawless Face' look is that beauty starts with amazing skin—which explains why we're so mad about her makeup. You can flaunt that famed flaw-free complexion with her collection of pro-grade products, like Foundation Primer, which primes the skin just as a painter primes a canvas. (Who said an art school degree doesn't come in handy?)