Jamie Cat Callan is the author of of the wildly popular Ooh La La: French Women's Secrets to Feeling Beautiful Every Day, Bonjour Happiness, Forever Chic: Frenchwomen's Secrets for Timeless Beauty, Style, and Substance,  and French Women Don't Sleep Alone: Pleasurable Secrets to Finding Love.

Here are Jamie's tips for women on what to wear in Paris:

• The little black dress.  This can be sleeveless or not, depending on the weather.  Wear it during the day or dress it up for evening with some stylish bijoux.
• A pair of jeans or simple black pants that fit absolutely perfectly.  Again, this can go dressy or casual, depending on what you accessories you add.
• A great knee-length skirt in a style that’s flattering to you.  It doesn’t have to be a pencil skirt—unless that’s what you love.
• The white shirt (again, if this is your thing).  Otherwise, a gorgeous cashmere pullover or a simple blouse in a solid color.
• Two or three tank tops in your favorite accent color.  These are lovely for peeking out of a jacket or cardigan and the unexpected hint of color adds a little intrigue.  If you’ve got fabulous upper arms and shoulders and the weather is hot, you can wear this with jeans or skirt. 
• A stylish jacket that’s versatile enough to go with jeans or a skirt or with the little black dress.  Another idea is a pretty cardigan in a color that goes with everything.  Speaking of color, black doesn’t have to be your basic palette color.  Lots of French women go for navy or cream.  And some daring ones will wear the little red dress, as a change from the little black dress.
• Scarves.  Bring several.  They’re perfect for accenting your dress.  Bring one for evening wear, one for daytime and one for fun.  Choose colors that pick up and link to the color of your purse or shoes.  The scarf is the French woman’s magic secret to making more out of less, and it’s the perfect travel accessory.
• Good walking shoes, because Paris is all about walking.  But you can also wear something stylish.  For the warmer months, bring a pair of cute ballet flats and for the winter, bring a pair of good leather boots with a low heel.  And for evening and for the occasions you want to dress up a bit, bring one pair of high heeled pumps, or what I prefer—a pair of stylish ankle boots.

Jamie Cat Callan's website is dedicated to living, loving and traveling as a French woman.