'Your hair's really dry.' This isn't a phrase that Jo's heard for years and years and years, but a combination of over-bleaching and salt (she was in the sea pretty early this summer), a longer-than-usual cut and higher-than-normal stress rating had left her hair unusually straw-like. 'Frankly, those words are a bit like a dagger in my heart; I've always prided myself on shiny, easy-to-manage hair...'

But Jo knew what to do. Years ago, when something similar happened, she headed to the salon of Léonor Greyl - something of a legend, in Parisian circles, for her holistic approach to hair care. And this is CARE. Proper TLC. Not a quick mask and a bit of head massage; an hour or more spent putting the life back into hair.

'I booked myself in for the 90 minute treatment at the Rue Tronchet salon,' recalls Jo. 'Off a classic Parisian courtyard, up in a tiny one-person lift, the doors open and basically, you've entered "Hair Heaven". Packed with chic Frenchwomen who understand: you wear your hair every day, so it's worth investing in. (Boy, I bet it'll be rammed after what the French call "La Rentrée", at the end of August, when everyone heads back to Paris from the hair-frying Côte d'Azur.)

'I was ushered into the Private Suite, and invited to sit in a comfortable chair. Sylvie, who was to perform my "soin" (as the French call a treatment) reclined me, and began by spraying Léonor Greyl's special vegetable-based Huile de Léonor Greyl oil on my hair, working it through with a bristle brush. It's applied to roots and scalp, too - because that's the most important zone, according to Madame Greyl.

Massaging the product to make it penetrate better, I find myself already beginning to relax - no mean feat since my Eurostar had been two hours delayed, and I'd had to lug my heavy suitcase to the salon.

'A special paste was applied to my scalp, made up of ingredients including wheat germ and yeast, to cleanse - a little like a "scalp scrub", to invigorate. At some point (and I think I'd drifted off for a while), a "ventouse" machine was also moved over my scalp, with a sucking action, to stimulate the follicles. When I interviewed her years ago, Madame Greyl explained how important scalp circulation was, for healthy hair growth - and stressed the importance of massage. I still remember her telling me how stressed women's scalps were really tight, and didn't move over the bones, whereas in a relaxed woman, the scalp moves much more freely. (With more than a little stress setting up The Perfume Society- now successfully launched, I'm happy to say - I'm not surprised mine was a little on the taut side.)

'My shoulders and neck were also blissfully massaged, and a succession of masks applied - including the Masque Quintessence (right), which blends rich oils of cupuaçu and manketti, and is unbelievably gorgeously-scented with mock orange and linden. Hair masks don't get much more luxurious than this (and I'm now lugging a tub of it to my regular hairdresser). Like all of Madame Greyl's creations, it's almost entirely natural, with many ingredients organically certified by Ecocert.

'Once all this was washed and rinsed out, I eased myself reluctantly out of the chair to have my hair dried and styled. "Mousse, please" I requested of the stylist - who slightly scarily shook his head. "Madame Greyl does not recommend the use of styling products after 'un soin'", he insisted. Which made me nervous: my hair needs extra oomph, generally. But with an incredibly clever flicking comb action, he managed to get as much volume in my hair as my usual stylist does, simply through a clever wrist action. To say I was amazed doesn't even begin to cover it.

'After just 90 minutes, my hair was literally transformed - from straw to silk. I've kept up the good work by extending the length between colouring sessions by about 10 days (I was definitely over-doing it), and using the Masque Quintessence at home. It's an arm and a leg - but hey, unlike a pair of shoes or a jacket, I figure: I wear my hair every day, and it's worth the investment.'

'I cannot praise this treatment too highly - to the point where each time I know I'm going to have to head Paris-wards (and it happens a lot, as a perfume writer), I'm going to book myself in for another treatment.

'Because quite simply, I don't ever want to hear those words "Your hair's a bit dry" again, as long as I live.'

Institut Léonor Greyl, 15 Rue Tronchet, Paris 75008 +(33) 1 42 65 32 26 www.leonorgreyl.com

UK readers find Huile de Léonor Greyl at www.cultbeauty.com/£26 for 95 ml - buy here And find Léonor Greyl Masque Quintessence Repair Mask for Damaged Hair at www.cultbeauty.com/£78 for 200 ml - buy here