The Roitfelds are the crème de la crème of the parisiennes soignées—they always look sophisticated yet natural, groomed but not falsely so. The word soignée provides a clue, it is from the Old French soigner meaning "to take care of". As Julia has stated in interviews, her best advice is to begin caring for yourself at a young age.
One way to create that coveted soignée look is to go lightly on the makeup and keep it balanced. Reputedly neither Julia nor Carine wears foundation, just moisturizer (and juice) provides the glow. They do, however, combine the smoky eye with just about anything, making their gorgeous eyes the focal point. If you want to follow Julia's lead, she uses Chanel Le Crayon Khôl in black to line her eyes and then follows this with Chanel Inimitable Mascara also in black (and never waterproof).
I have used the Chanel eye pencil for several years and I would never consider using a different product. It provides exactly enough coverage so that you end up with a nice dark line and virtually no smudges. As an added bonus, it comes with its own sharpener. I switched to the Chanel mascara that she uses this past December and I am so happy with it. Though it is not waterproof, it only smears if I cry which mercifully is infrequent. It does a fantastic job of defining every lash without making it look artificial. I've looked for a good mascara forever, most recently being disappointed with Diorshow, and this is another product I recommend without reservation. When it comes to eye makeup, Julia and I agree: make it Chanel.
Image of Julia Restoin-Roitfeld's eye courtesy of Harper's Bazaar UK