PARIS (AP) ― Before Britain’s royal wedding, when the identity of the designer behind the dress Kate Middleton would wear to the alter was still the best-kept secret in the kingdom, some in the fashion world cast doubt on the rumors pointing toward Alexander McQueen, saying the label’s aesthetic was too dark for a princess-to-be known for her demure style.

Though McQueen creative director Sarah Burton did end up scoring the plum commission, the label’s spring-summer 2012 ready-to-wear collection Tuesday served as a reminder of just how somber the house’s look really is. Nip-waisted skirt suits borrowed elements from bondage gear, while stunning pearl and mother-of-pearl covered gowns felt like beautiful straitjackets.

There was nothing constricting about the Valentino collection, where the airy concoctions of organza and lace were as light as a whisper.

Karl Lagerfeld said that with everyone and their mother churning out knockoff Chanel skirt suits in heavy-duty tweed, he’d decided to send out the label’s iconic suits in the lightest of high-tech materials.

Lagerfeld bragged that his iridescent sheath dresses, made from Space Age polyester shot with fiberglass and paper ― “not that horrible polyester from the seventies’’ ― “weigh literally 3 grams.’’

Beyond the technical virtuosity of the materials, Chanel impressed with its ever-awesome set. This time, the luxury powerhouse ― which has just about the deepest pockets in the industry ― transformed the steel-and-glass domed Grand Palais into a pristine seabed, its sand-strewn catwalk dotted with towering clumps of seaweed and coral made from bright white fiberglass.

New beginnings dawned at Paco Rabanne, the iconic sixties label that relaunched its shuttered women’s line after a years-long hiatus, and at Jean-Charles de Castelbajac, where a new owner has resulted in uncharacteristic austerity.

After eight grueling days under the blazing sun of a freak Paris Indian summer that finally broke on Tuesday, the collections come to a much-anticipated end Wednesday, with Prada second line Miu Miu and Elie Saab, the Lebanese designer who’s omnipresent on red carpets the world over.

But before breathing a sigh of relief, fashionistas were setting multiple alarms to be sure to make the Louis Vuitton, which is, cruelly, in the 10:00 a.m. time slot.

Unlike pretty much every other show, where a half-an-hour late start is considered on time, Vuitton actually starts at what the rest of the world would consider promptly, and sometimes early, even.

Last season, stragglers made a blind dash for their seats when the lights went down and the music came up two minutes ahead of time. Rumor has it that Vuitton will start a full five minutes early this season.


Chanel

Like a luminous Venus rising from the sea atop a half-shell, pearl-covered Chanel models in light, liquidy fabrics emerged from a giant sea anemone onto a catwalk transformed into a sprawling undersea kingdom.

There was nothing literal in uber-designer Lagerfeld’s take on the ocean theme: None of the clothes were covered in sailor stripes or emblazoned with kitschy red anchors. The collection was more about play of sunlight on the surface of the ocean ― shine, reflection, radiance.

“I absolutely wanted to avoid mermaids and things like that,’’ Lagerfeld, sporting a seashell pink shirt and matching tie for the occasion, told reporters in a post-show interview. “I was inspired by the movement of seaweed, its lightness, and by certain fish that have very modern shapes, like sting rays.’’

Frothy puffs of chiffon clung like sea foam to the hemlines of some of the narrow skirts, and shiny aqua ribbons zigzagged down the white shift dresses like angry waves. A cocktail dress had puffs of slick ribbon embroidery at the sleeves and the hips, like clumps of black seaweed.

Everything was covered with pearls: They stood in for buttons and replaced chain belts, punctuated the models’ slick, wet looking hairdos and were stuck onto their ears and backs ― in neat rows down their prominent vertebrae.

Ahead of the show, which attracted A-list guests including Uma Thurman, Lagerfeld himself emerged, like Neptune, to survey his underwater kingdom. He hammed it up for the scrum of photographers that immediately materialized around him, pretending to strum a fish-adorned harp as the flashes popped furiously.

Like tourists at the Eiffel Tower, guests posed for snapshots on the set: Two Chinese couples dressed in head-to-toe black ― the women in floor-length Chanel evening gowns, the men in tuxes with bow ties for the 10:30 a.m. show ― contrasted smartly with the backdrop of gleaming white coral.

A border terrier named Frickey in an Yves Saint Laurent leopard print collar ran in excited loops around the set, sniffing at the mammoth fiberglass seashells. Thankfully, he was well-trained and didn’t dare mark his territory.



Alexander McQueen

The ivory silk wedding dress that Kate Middleton chose for her date with history was, of course, Alexander McQueen, but it was hard to imagine the demure now-Duchess of Cambridge sporting the S&M-infused black teddy, the head-enveloping lace-and-leather face masks or any of the other extreme looks that came down the label’s runway Tuesday.

The house was built on just such harsh beauty, but following the Feb. 2010 suicide of its namesake and founder, it appeared as if his successor would steer the label in a softer, more consensual direction. For her debut as creative director one year ago, Burton delivered a collection that loosened the screws on McQueen’s punishingly nipped waists and smoothed out some of his harshest angles.

And then there was the dress, the wedding down that saw Middleton transformed from commoner into royalty ― the single most coveted commission in recent fashion history. Kept under the strictest of wraps up until Middleton alighted at Westminster Abbey on April 29 ― before some 2 billion spectators worldwide ― the simple-lined, long sleeve concoction became an instant legend and unleashed a bridal wave of copycats.

But the Duchess of Cambridge has notoriously low-key style, and trying to imagine her in anything from the spring-summer collection was absurd. After all, what would she do with her luscious locks ― not to mention her face ― in one of those lacy pantyhose head masks that topped off all the looks? (Covered in pearls or sporting a metal beard made out of what appeared to be straight pins, they were the world’s chicest and most twisted Mexican lucha libre masks).

With Tuesday’s collection, Burton’s third as creative director, she tightened the screws again. Suits with flippy skirts and shrunken jackets were cinched at the waist with oversized belts and kinky lace-up detailing. Evening gowns entirely covered in pearls or mother-or pearl scales were ravishing, but looked about as conformable as straitjackets.

The show elicited among the most positive reactions of any of the Paris collections, and Burton looked almost embarrassed by all the hubbub as she ducked onstage for a bow.



Valentino

Valentino’s concoctions of lace and tulle had all the delicate transparency of exotic jellyfish, their luminous membranes pulsating gently in deep-sea depths.

For spring-summer, the design duo that has remade the Italian label in its feather-light image following the retirement of founder Valentino Garavani continued to refine their now-signature airy looks, sending out a collection of see-through dresses in lace, tulle and organza.

Maria Grazia Chiuri and Pier Paolo Piccioli delivered chemisier dresses embellished with dramatic flame-shaped panels of lace, A-line bustier dresses like frothy millefeuilles of chiffon and organza and the simplest of ankle-length gowns, with a slight seventies vibe.

Besides a couple of the long dresses in the shade of lipstick red that was so synonymous with the label under Garavani’s tenure that it earned the title “Valentino red,’’ the rest of the looks were in the kind of makeup shades Piccioli and Chiuri have favored in recent seasons ― buff, ivory, seashell and salmon pinks, with a sprinkling of gold.

While these looks are not for everyone ― actually, they’re meant pretty much exclusively for very young women with sticks in the place of legs ― they have a very distinct and delicate beauty all of their own.