For decades the image of the slender and chic Parisian woman has been setting the standard as the epitome of style and making some other women in France feel uncomfortably inadequate.
Isabelle, a 50-year-old director of a fashionable Paris art gallery, says: "C'est simple. Chic plus mince egale succes. (It's simple. Chic plus slim equals success)."
She is talking about French women and their figures.
"It's how it works for women here," Isabelle explains. "If you are fat, you will not get that job. But if you have the silhouette - chic, ultra-slim, elegant - you are more or less made."
Isabelle is an all-too-rare exception to the rule - she is actually quite fat - but, being self-employed, she can get away with it, she says. Isabelle likes being overweight in a society that is so obsessed with thinness and conformity.
"Being fat makes me feel free, even though I can never find anything to wear in the Paris shops. I remember vividly the last time I tried, the look of horror on the shop assistant's face.
"'Madam, we certainly have nothing for you here,' she cried."
It is said that every French woman feels she needs to lose at least 2kg (4.4lbs) and the slimming business in France is huge.
Pharmacies are filled with miracle-claiming diet products and women's magazines run endless columns of slimming advice.
Most of the pressure French women feel to be thin comes from other French women and a society that has zero tolerance for fat.
"Fat" is a dirty word, an offensive insult. It is difficult to come right out and say it. Thankfully, there is an array of flattering euphemisms to choose from.
One is not fat, one is ronde, robuste, forte, solide, dodue, rondelette - round, robust, strong, solid, plump, chubby, or even enrobee - enrobed - an adjective otherwise used to describe a mouth-watering coating, usually of thick chocolate, on sweets and cakes but in this case it refers to a woman richly coated in her own body mass.
There is an idea put about in what the French call the "Anglo-Saxon" press that French women do not grow fat.
They simply follow a set of mystic rules, handed down from mother to daughter, that govern their personal grooming, comportment and, most of all, their eating habits.
A sensible, balanced diet. Plenty of fresh produce. Three meals a day. Absolutely no snacking. Regular, reasonable exercise. Nothing to excess.
It is what any educated Western woman would teach her children - male as well as female - whatever their nationality.
Although many women do follow this regime and maintain healthy, reasonably slim figures, to have that wafer-thin silhouette many need to almost starve themselves.
There are plenty of Parisian middle-class families who will sit down to a frugal meal of steamed vegetables and a cup of herbal tea in the evening to avoid weight gain.
"There is simply no mystery about it. Of course French women grow fat," says Sonia Feertchak, editor-in-chief of L'Encyclo des Filles, a popular guide to health and beauty for teenage girls.
"But the fact is they daren't, and some will even starve themselves because in this society to be a fat female is to be a failure."
"Fat women are seen as stupid. Their lives must be out of control. They are judged ugly, weird losers," explains Sonia.
"Women have come so far in France - we have a political voice, good childcare, access to work - but instead of being more confident, we are increasingly obsessed with our weight and shape.
"Coco Chanel freed us from the corset more than 80 years ago - but we have fallen for a mental one instead - a silhouette of supposed perfection that is unattainable and leads to eating disorders and misery," she adds.
Everywhere one looks in Paris she is there, that idealised French female, pouting glamorously from buses, billboards and metro stations; petite, fragile and very slim; advertising anything from lingerie and lipstick to discount car-insurance, even food - ice-cream parfait, perhaps, or a rich French cheese poised tantalisingly just beyond the reach of her gorgeous, half-open mouth.
"It is an absolute tyranny," says Marjorie, a 49-year-old business executive, herself pencil slim.
"The tyranny of the silhouette, we call it - but it is also a kind of dream because it represents total success.
"It is not like in the UK where TV shows have women of all shapes and sizes doing all kinds of things. I love that - chubby 55-year-olds kissing men full on the mouth. You would never see that here," she adds.
Marjorie works near the Paris suburb of Saint-Denis where there is a large immigrant population from the Maghreb.
She is inspired by these women with their full, rounded, curvaceous figures and the way they walk tall.
"They are so much more feminine than our Parisian chic," she says, "but the sad truth is that if they want careers in this society, they are going to have to get skinny to get ahead."
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