To dress “like a French girl” means to look not just chic, but charming too. Allow me to try to translate (I dress French better than I speak it these days). The “girl” bit matters, because it softens the Gallic hauteur. Our French girl is not a Parisian madame, ribs rattling against her Chanel suit like ice in a glass. The FG’s hair is a little messy (though her fringe is somehow always perfect) and her clothes are not box-fresh (neither are they scruffy). Her outfit never does too much (Emily in Paris is not an FG) but its details – jewellery, a scallop-edge scarf, a vintage bag – make her intriguing. You will find the FG doing something perfectly prosaic – reading her book on the metro, buying bread – in a way that is irresistibly alluring. The latest prosaic thing the French girl makes bafflingly charming? Wearing a cardigan. When an English woman wears a cardigan, it’s a vibe, but not a hot one. On the internet, it is called “frazzled English woman”. Her cardy is one of a hodgepodge of layers assembled for practicality and warmth. She grabs a cardy from the back of a chair and yanks it over her shoulders with all the grace of a woman slinging a tea towel on the peg. The French Girl Cardigan is a whole different vibe. It is soignée, nonchalant, sexy. The actual cardigan is, funnily enough, the kind you almost certainly already own. It needn’t be anything fancy. It can be that crewneck, medium-length one that might once upon a time have been half of a twinset. The magic sauce is in what you wear it with, how you put it on, and the attitude you bring. The actual cardigan needn’t be fancy. The magic sauce is in how you wear it and the attitude you bring The name may sound silly, but the French Girl Cardigan is a useful, versatile addition to your wardrobe. It can be a cardigan worn almost as if it was a pashmina, draped over your shoulders for warmth. This looks particularly good as a surprising top layer – for example, over a T-shirt and a blazer. Good for softening a tailored jacket into a more laid-back look – not to mention an extra layer when the temperature drops. (The shoulder-scaping of honorary French Girl Alexa Chung is your style reference here.) Or it can be worn as if it was a T-shirt – tucked into your high-waisted jeans or a pair of belted, front-pleated trousers. It’s best with just a bra beneath, the top few buttons undone, with a necklace or two against your skin. The French Girl Cardigan can be worn unbuttoned, as if it were a jacket, especially if the cardigan is straight and boxy, rather than elasticated at the hem, and best of all if it has pockets or chunky buttons that add a bit of rigour. Try this with jeans, a shirt and loafers: this kind of cardigan can be what the denim jacket was to a 1990s summer wardrobe. Last time I was in Paris, I also noticed cardigans being worn with just one button done up, at solar plexus height, sometimes with a crop top (or no top) underneath, so a sliver of tummy is revealed. It can be worn back to front, with the buttons down the back, which always looks slightly saucy. Or it can be teased into a deep V-neck shape by strategic extra unbuttoning, so that it starts to fall off one shoulder. The spiritual home of the French Girl is affordable luxury brand Sézane, a one-stop shop for everyone who wants to be a bit French. (Including the actual French: I can confirm that everyone wears it in Paris.) Its Gaspard cardigan (£95) is a classic crew neck, the Barry (also £95) is the perfect V that works equally well back to front, while the Betty (£130) is a collared cardigan-jacket cross. Accessorise with a Chanel 2.55 bag, if you have one. But if not, a baguette will do just fine. Styling: Melanie Wilkinson. Styling assistant: Sam Deaman. Hair and makeup: Sophie Higginson. Hair by Sam McKnight and Osmosis skincare. Cardigan: Sezane. Jeans, by Topshop from ASOS. Loafers and earrings: Jigsaw. Model: Els Wright from Milk