Documents from APC founder Jean Touitou’s youth, in his new book “Transmission.” The free-ranging scrapbook and history chronicles Touitou’s 30 years in fashion. (Handout via The New York Times)

PARIS — There is an indelible truth about APC, the willfully anonymous French fashion label that has been quietly going about its business for three decades, one that is both right and not quite right. It concerns the clothes that APC makes, and also its ambitions, the APC epithet and albatross: “This eternal thing: ‘They do basics,’” said Jean Touitou, the APC founder, sitting at his dining table, battling back his bugbear of decades. “This has been for 30 years.”

Because Touitou, 65, is a gravelly philosopher of bearish proportions, given to lengthy digressions on his pet causes, and because, although he is thoughtful, he can also be fierce, you might, with a nervous twinge, cast your eye down to the dark indigo jeans you are wearing (which you acquired in 2006), or think back to the powder-blue oxford shirt at home in your closet, unshowy but unfailingly appropriate, and think to yourself, “Well … don’t they?”

They do and they don’t. APC’s clothing is defiantly normal — regular, needful, closet filling — and has been since it was founded, so modestly that originally it did not even have a name. (Touitou tagged it only “Hiver 87” — that is to say, winter 1987.)

The journey of 30 years, chronicled in a free-ranging scrapbook and history Touitou has compiled and which will be published next month as “Transmission,” has in some ways not taken it far from that original ideal. In a business like fashion, where surface appeal can be a kind of sorcery, and surrealism often mistaken for genius, to make simple clothes is to invite being overlooked.

But as upstarts have flamed out and even historic houses faded, APC has soldiered along. Go into one of the cooler neighborhoods of the cooler cities in the world — New York, Los Angeles, London, Paris, Tokyo — and there is not one APC store, but several.

“People, especially girls, say, ‘I don’t know why, but I like this,’” said Judith Touitou, 45, Touitou’s wife and APC’s artistic director. “We do things out of honesty. We never put out a garment we could not wear ourselves.” Perfecting unostentatious clothes is fashion, Jean Touitou insisted, and is not easy.

Together, they set the course for APC: Jean Touitou is the inspiration and ideologue, Judith Touitou the day-to-day manager of the studio and the creative direction. (They met at APC, where Judith Touitou started working in 1996, after studying business and then politics at the prestigious university Sciences Po in Paris, to help Jean Touitou run the company. He was, somewhat inconveniently, in a relationship at the time.)

From the earliest, APC was an outpost for reliable standards and, especially, jeans. Its ramrod-stiff Japanese selvage jeans are and have long been the label’s best seller, to Jean Touitou’s occasional irritation. (“You’re the Stones? Sing ‘Satisfaction.’ You’re APC? You’re good at jeans.”) They have been quietly influential.

APC “is the closest thing that the fashion troops have to a barracks,” The New York Times wrote back in 1994, one year after Touitou opened a store on Mercer Street in Manhattan. “Stylists roaming SoHo stop, unwind, buy something and go back into the fray again.” They still do — and sales are up, 7 percent this year, and an average of 10 percent year over year for the several years before, according to the company.

“It very easily became part of my uniform,” said actor Waris Ahluwalia, who went from being a fan of the label to becoming a friend of Touitou’s, and who collaborated with him one season on a collection of lapel pins and jewelry. “It’s always the stuff you underestimate that you should watch out for.”

APC is easy to underestimate. Its scale remains relatively small: The company is on track to reach 62 million euros (about $73 million) in sales for the year 2017, said François-Cyrille de Rendinger, its chief executive. It eschews big shows, red carpet dressings, overweening ad campaigns and hysterical logomania.

But it does have celebrity placements, and big ones. Touitou struck up a friendship with Kanye West, and worked with him to put out two capsule collections. Catherine Deneuve, an icon of Touitou’s youth (“’Belle de Jour’ when you’re a young boy is a big discovery”), is now a private client, with clothes made to order.

Yet APC struggled to be taken seriously as fashion, despite Touitou’s protestations that it has been from the very beginning. The fashion establishment tends to elevate those designers who play up the artistry and high-minded theatrics of what is, on some level, the rag trade. Creating clothes to make and sell is thought to be vulgar, Touitou said: “You’re a merchant. You’re dealing with merchandise. You sell. Whereas you should be a genius, creating concepts.”

Here enters the class consciousness that runs through the APC story. “Karl Marx was milk,” Touitou said. He did not set out to be basic or to be a merchant. He set out to foment the revolution.

Born in Tunisia, Touitou immigrated to Paris at 9, in 1960. At the Sorbonne, he grew obsessed with Trotskyist politics, becoming a practicing member of the Organisation Communiste Internationaliste. “In those days, my point was, ‘Man, we have to redesign everything. We have to destroy the whole city,’” he said. He was a firebrand in U.S. surplus-store corduroys and Shetland sweaters, peddling revolution door to door.

“When you come from politics, you want to change the world totally,” he said. “Then you can realize this is not going to happen. You go at 5 o’clock in the morning to factories to try to sell your ideas, they don’t want that. You’re just a romantic. They don’t want revolution. Period. Communism was maybe just a good idea for books.”

Instead, Touitou turned to rock music (he idolized ‘60s garage rock bands) and, eventually, found a job with the fashion label Kenzo, in Paris. He began in shipping, worked his way up to overseeing the department, decamped for Agnès B. and, finally, began APC (Atelier de Production et de Création) in a tiny studio on Rue Princesse in 1987, as a new outlet for the same fixations.

“To be frank, I wanted to be the continuation of what I always did: radicalism,” he said. “A very strong statement against almost everything.”

These days, Touitou is not exactly the picture of the grizzled radical. He and his wife live with their daughter, Lily, 12, in the 7th Arrondissement, among the haute bourgeoisie. (He has two children, Haydée, 28, and Pierre, 24, from his previous relationship.) He is spending his summer vacation cruising the Peloponnese on his boat. Still, he said, APC makes the same kind of corduroys and sweaters he used to rabble-roused in. His cousin, novelist Guillaume Dustan, who died in 2005, once joked to him that he had more influence on the French than the Socialist Party.

“It’s a funny thing to say,” Touitou said. “But I think it’s true.”

What clothes there are on the luxury racks are not often the clothes Touitou prefers.

“The bourgeois don’t know how to dress anymore,” he said. “With women, it’s just a disaster. I think the group luxury brands have a huge responsibility into that culture of vulgarity.” He recalled a recent visit to Cannes: “You’re seated by the pool, and everybody looks like he’s just found a hooker.”

Under the Touitous, APC seeks to offer a lesson and a corrective; in its way, it is even budding into a small group of its own. Touitou finds little latitudes to extend to talented employees: His co-designer, Louis Wong, has a small line of high-end jackets, Louis W., under the APC umbrella; and when Vanessa Seward, a veteran of the Yves Saint Laurent and Chanel studios, joined APC in 2012, she was given first a capsule collection, and then eventually her own womenswear line, which has grown to support four stand-alone stores in Paris and London.

De Rendinger didn’t rule out other labels being developed in the APC laboratory, although he did caution that they would go slowly.

So the revolution, such as it is, continues. APC’s basics are edging toward the less basic. Judith Touitou has enlisted Charlotte Chesnais, the jeweler and longtime Balenciaga designer, to consult on the APC women’s collection. “It’s a moment where we want to be different from ourselves,” she said, “which is strange.”

Nevertheless, the cardinal rules still apply. Your clothes should make you feel like you. A little bad taste can be good. A touch of ugliness can be nice. The clothes APC makes will never be other than what its stewards would wear themselves. “It’s nice to be loved when ——” Judith Touitou began.

“When you’re not lovable,” her husband supplied.

But that wasn’t quite it.

“When you’re not trying too hard,” she said.

APC isn’t luxury fashion. It’s probably closer to the Atelier de Laissez-Faire. “I think it’s really hard on people,” Judith Touitou said. “At a dinner party, they will look perfect, but if it’s a promise they can’t fulfill in everyday life, it’s really sad.”