Nonchalant elegance, understated chic, bold yet never flamboyant. Parisian style is practically synonymous with the image of a tall, slim Inès de la Fressange silhouette, sipping a glass of pinot, smoking Gauloises, and walking down the street as if strutting down the catwalk.

“Parisian style has turned into a myth,” says French journalist and personal stylist Isabelle Thomas, co-author of Paris Street Style: A Guide to Effortless Chic, which comes out from Abrams this week. “It is not as stereotyped as people think. Fashion is indeed at the core of French culture, but we don’t always go out on the streets wearing a beret or a pair of cigarette pants like a Saint Laurent model. And we don’t all have the right figure for it!”

In her new book, co-written by photographer Frédérique Veysset, Thomas argues that there are fifty shades of French style: “Frédérique and I have very different approaches to fashion, ” she says. “Yet, each time we go abroad together, people always say that we have that little je ne sais quoi that makes us look French. That’s how we got the idea to write this book.”

In Europe, they say, the definition of female elegance differs depending on where you live. The book starts by distinguishing the French—more sober in their fashion choices than the Italians and the English. Thomas explains: “Italians are very fashion-conscious. They tend to follow the trends religiously and often have flamboyant personal styles. On the other hand, the English are more extravagant. They are much bolder and more daring than us, which is a good thing.”

While the book enumerates a series of fashion faux pas that should be avoided (no velvet hair grips, black tergal pants, quilted jackets, jogging clothes in velour, or wearing Converse after your 26th birthday), it isn’t the typical list of do’s and don’ts. Thomas and Veysset also interviewed renowned figures of the French fashion industry, such as designers Maxime Simoens, Alexandre Vauthier, Inès-Olympe Mercadal, and Christophe Lemaire, artistic director of Hermès’s womanswear. “I didn’t invent the wheel,” says Thomas, “but I believe that French style is like a skill that can be learnt and nurtured in many different, individual ways.”

More than a skill, French style is also a way of life. In fact, she says, the way French women relate to fashion bears strong similarities with the way they relate to food. French women are very practical. Their golden rule is moderation—especially in the good things. “There’s something a bit bourgeois about it,” she adds.

As fashion devotees from all over the world are now gathering in Paris for Fashion Week, Thomas insists that French style is more about transcending the conformity of trends than being too fashion-conscious. “It’s all about being in sync with oneself,” she says. “People shouldn’t be looking for a disguise through fashion.” The best thing to do, she suggests, is to play with clothes: invest in timeless pieces—such as a trenchcoat, V-neck cashmere sweaters, or a short leather jacket—and mix them with vintage clothes and a few pieces of menswear here and there. But never underestimate the power of a well-chosen accessory, be it shocking pink pantyhose, a pair of jeweled sandals, or an oversize cheche scarf. “It will add an extra oomph to your style,” she says.

Most importantly, French style is all about looking naturelle. The greatest difference between French and American women, Thomas explains, is that the latter are trying too hard to get a perfect, polished look. Interviewed in the book, French actress and singer Emmanuelle Seigner said: “American women are pulled together perfectly from the moment they wake up in the morning: perfect hair, varnished nails, high heels ... as if they were bound for a cocktail party or some red-carpet affair. French women don’t bother their heads so much.”

Nevertheless, nonchalant chic takes work, Thomas admits. “Even if it takes ages to get ready sometimes, it doesn’t show. That is French women’s golden rule par excellence.”