In the behemoths that are global fashion houses, personal stories can often get lost. Big brands signify big bucks and give life to images of multimillionaire moguls and conference rooms; of roll-outs, strategies and suits; of names that jump from the pages of fashion bibles and trip off the tongues of fashionistas.

Agnès b is one such name.

At heart, however, this brand is a more personal affair. It encapsulates the story of a woman, born Agnès Troublé, with humble ambitions and little regard for fashion, who went on to become one of France's best-known entrepreneurs; a self-made millionaire who doesn't shop; a mother of five and a grandmother of 15 who distributes free condoms in her stores; and a filmmaker.

Welcome to the world of Agnès b, the person.

"I don't care for fashion so much," says Troublé in a thick French accent, as she perches on the edge of a sofa in Hong Kong's Peninsula hotel. "Fashion that comes and goes is not that interesting to me. The best thing is to be oneself, to find your own personality and keep that idea in mind."

Staying true to her own ideals has helped Troublé build her business, which started in a converted butcher's shop in an unfashionable district of Paris, into one that now boasts 282 stores - including cafes, florists and patisseries - and more than 2,000 employees, scattered across the world.

"I've been here [in Hong Kong] for 19 years, and the team have been developing agnès b very well, taking my ideas on the fly. Like these flowers," she says, gesturing towards a perfectly imperfect bunch of peonies. "I wanted to be a florist when I was 15, so now they do agnès b flowers, and they do it perfectly."

The 73-year-old sitting before me, with unruly platinum ringlets, a slick of red lipstick on her otherwise unmade-up face and a large silver ring embossed with the words "Give Love" on her finger, was raised in the grandest of surroundings.

"I grew up not in fashion, but in Versailles," she says. Her family had a house on the doorstep of the royal palace, on the outskirts of Paris, and she "was basically raised in the park, there. It was so inspiring, so beautiful." Her father was a lawyer, her mother an officer's daughter, and Agnès attended the local school, studying drawing at Versailles Ecole des Beaux-Arts by night. "I was always drawing in the park, every evening for hours. I wanted to be a museum curator when I grew up."

When she finally did grow up, however, she rebelled. Fresh out of school and aged 17, Mademoiselle Troublé ran away and married publisher Christian Bourgeois, the man responsible for the 'b' seen on countless clothes tags today.

"On my 19th birthday, I had twins, and then I left my husband to change my life," Troublé says, in her matter-of-fact way.

Being a young single mother in 1960s France must have been quite challenging.

"Yes, it was shocking," she says. "It was certainly shocking for my parents at the time. But I wasn't scared. I'm very optimistic, naturally. It's helped me a lot.

"I didn't want to ask my family for anything because they were quite furious that I was separating from my husband. So, I wouldn't say I was poor, but I didn't have any money. We lived high up in a building in Montparnasse. There was no furniture, just three little beds, but we were not unhappy."

Completing the picture of a bohemian Parisian in the 60s, Troublé joined the student riots that rocked the city in 1968. "I was in the streets with everyone. I had a small car, a Mini Moke, that I used to take the wounded to hospital. It was frightening, but it was great. We were walking in Boulevard Saint Michele and Saint Germain, and you could hear all the speeches.

"When it was finished we were so, so sad."

With two young sons to raise, however, life as an activist wasn't ever on the cards, so, even before the students had taken to the streets, she found herself working at French Elle. Her route into the magazine is now fashion folklore; Troublé caught the eye of the magazine's editor-in-chief at a dinner party.

"She recognised me as someone dressed in a special way. Because I had no money, I used to mix things from the flea market. I was wearing a khaki army jacket with a white petticoat and western boots. It was a new look then, and they hired me as a junior fashion editor," Troublé shrugs. "That's the way it started."

Elle, however, wasn't her cup of tea: "I found it boring, I wanted to create."

In 1967, after a couple of years at the magazine, she left to become a designer for home-grown brand Dorothee Bis, before going on to freelance for the likes of ready-to-wear, perfume and accessories label Cacharel.

"I worked very hard, but it was a great [education]."

Nonetheless, it must have been tough for a single mother.

"Look, I always did both - family and work - but I took care of my children. I went home at 7pm and did homework and baths and food, so they've not been at all unhappy. I always tell them, 'I could have been at the supermarket cash tills and you wouldn't have seen me more.'"

It was in 1975 that the agnès b we know today was launched.

"I began with my second husband, Jean-Rene de Fleurieu. He was very young, I was very young; we wanted to have our own place." They found it in Les Halles, Paris. "Yes, that's where I really started, in an old butcher's shop on the Rue du Jour!" she laughs.

The couple decorated the space together. "We were taking the grease off the walls and hanging the skirts on the hooks where they used to hang the meat."

The shop still stands, as her flagship menswear store, but back then it was an entirely new concept.

"We had a Rolling Stones poster on the wall and Bob Marley playing in the background. We also had 35 birds flying around. There were just two when we arrived, but they made nests in the ceiling out of little pieces of agnès b clothes and soon there were so many."

She and her husband set up camp in the store every day, along with their new daughter, receiving people like guests rather than customers.

"They were coming to see us and say hello and have a glass of something," she says. "We had food in the middle of the shop for lunch; it was very convivial. People were writing on the walls, having debates: 'Do you prefer Matisse or Picasso? Matisse first or Picasso second?' It was unique, that's why the press very quickly noticed that we were doing something different."

People came, too, to buy the clothes: simple, workwear-inspired basics similar to those still stocked in her stores today.

"They started buying them so fast! I was dying the clothes in my bathroom and they were buying them when they were still wet," she says. It was not long before signature pieces began to form: "Things like the striped T-shirt, and our famous snap cardigan. I had this sweatshirt in white, and I said, 'Why can't I open it in the front? Why not have all these snaps?"

Clearly, many others have thought so, too; so far, she has sold two million of them.

Troublé's aesthetic ran counter to the prevailing fashion trends: "In the 1970s, everything else was very decorated and complicated, and I didn't like it.

"I was fed up with the other companies I'd been designing for. They'd been asking me to do pockets, all afternoon long, all over things. So, eventually, I said, 'Look! A pocket is a pocket! You need two pockets and five buttons and a collar, and that makes a jacket.'"

She found a factory that produced workmen's overalls in the south of France, near Bordeaux. "They were making clothes for painters and other workers, so we changed the cut a little bit, did some new colours, and it was very successful."

Troublé may insist that there were no plans for expansion beyond their happy home in the Rue du Jour, but growth did come, and fast.

"The idea of starting our own shop had been to be quiet," she laughs. "And not to work for companies asking me to do pockets all afternoon long. But it was so successful that we opened a shop in New York, in SoHo, which was then very new. Then we developed another one on Madison Avenue and in Amsterdam, and then we started in London and Japan.

"We never advertised at all, because I think it's manipulation. I'm a child of 1968, a little left wing, and I think advertising is silly. Plus, I am proof that you can succeed without it.

"We had a lot of things in Elle magazine, and Marie Claire. All of them were very fond of my work, and I'm still supported by magazines a lot." (Magazines that rely for their existence on advertising, it should be noted.)

Troublé still designs every piece in her eight annual collections, a process that has and always will be entirely instinctive.

"I never shop. I never see any shows. I do things the way I feel I should do them. I'm not influenced by trends, I hate all these things," she says. "Everyone does the same in the end, and I don't want that. I prefer my own way, doing my designs, this one after this one. I want something for myself, so I make it, and then I do it for everyone. It's more a question of style than age, even with shorts. I love shorts!"

Agnès b produces 40 per cent of its goods in France; the old workwear factory near Bordeaux still makes the jackets and a manufacturer of French rugby shirts is responsible for her tees, "because they're everlasting and they just get better with age; quality lasts".

A large slice of Troublé's life, however, unfolds away from the design room. Art, photography, film and philanthropy all vie for her attention. She opened her first gallery, The Gallery du Jour, in 1983. Initially next door to the original shop, it's now beside the nearby Pompidou Centre and houses her world-famous photography collection.

"I think it's a privilege to give people things to see. I don't buy clothes, I don't buy shoes, I only wear agnès b. So, what I spend money on is things that come to my eyes." A sort of art-obsessed fairy godmother, she collects work by young contemporary artists and has a film company called Love Streams, through which she funds the projects of unknown directors. And she has just filmed a feature of her own.

"It's a drama, a road movie and an Asiatic voyage, too. There's a girl who's not happy at home so she escapes during a school camp."

Troublé's involvement in conservation work extends to her contributions towards funding the exploration ship Tara, which travels the world collecting climate-change data, an endeavour that costs €1 million (HK$10.2 million) a year.

Then there's her Aids activism. She was the first to give out free condoms in her stores, back in 1993. "It was the best thing everyone could do for the fight against Aids. I thought everyone was going to do this.

"I can't imagine not being involved," she says. "I'm very conscious about what's going on; I've read Le Monde [newspaper] every day since I was 17. As long as you have a voice, you must use it. I just have a bigger mouth now."

When she's not using that voice, Troublé likes to head back to Versailles. Le Coeur Volant, ("the flying heart") is a 17th-century villa commissioned by Louis XIV and her latest family home. "It's a simple house with a big garden, and I love it." She spends time in that garden with her children and grandchildren.

"I'm going to be a grandmother for the 16th time in September, and I have so much fun with them."

Does it ever get tiring, being the sole creative force behind a global fashion brand along with everything else? Does she miss the early days, of the bird-filled premises on Rue du Jour, Bob Marley in the background, Mick Jagger on the wall, her daughter playing at her feet and tables of guests discussing the merits of the Modernists over lunch?

"I'm not nostalgic, I accept change. But I want the company to keep the same way of seeing things, the same spirit. We do our best to share, to explain that love is very important.

"You can't do anything without love."