Tokyo-based French designer Julien David made his men's catwalk debut at the Paris menswear shows with a casual but elegant streetwear-inspired collection, while Mugler reinvented uniforms in a blaze of acid colours.
Up-and-coming David, 34, who has lived in Japan since 2006 and skateboards to relax, said the collection was all about subtle combinations.
"It's about mixing streetwear and high end with the placement of pockets, of a waist, these kinds of details," he told AFP.
"I find it interesting to make a suit with only a shirt and no jacket. It is kind of a street suit," he said.
His autumn-winter 2013/14 collection, shown to barely 80 people in the rooms of a labyrinthine apartment in the chic Marais quarter, teamed cropped flannel trousers with unstructured three-quarter-length coats.
Wool jersey leggings also featured heavily with reversible bomber jackets and brightly coloured check shirts.
Underlining the wearability of the pieces, David had them modelled by "real people" who wandered into his castings.
The street vibe continued with Mugler as creative director Nicola Formichetti, best known as Lady Gaga's stylist, and designer Romain Kremer sent out a uniform-dominated collection "fusing street and ceremony".
Bathed in white light, pink-lipped, heavy-booted models with slicked-back hair marched to a pounding beat.
"The trinity of tailoring, aeronautical and military regalia forms Mugler's most diverse garderobe (wardrobe) to date," the house said.
Slim-fitting but accessible suits alternated with body armour-style tops in acid pink and dazzlingly bright militaristic ensembles that looked more suitable for the crew of a spaceship.
Valentino, meanwhile, decided to adopt a very British air next winter with plenty of check -- hound's tooth and Prince of Wales -- to warm things up.
Against a palette of mostly navy, grey and black, Maria Grazia Chiuri and Pierpaolo Piccioli's collection featured injections of red and green as well as wide strips of leather just above waist level and touches of fur to highlight a lapel or collar.
Elsewhere, Alibellus presented an entirely black and purple collection.
Designer Tiki Kwan, who made up his models as Goths, said the collection was inspired by his impression of Parisian "creatures of the night" that took hold in his imagination as a youngster.
Raf Simons, artistic director of Dior's womenswear collections, rounded off the first day of the shows with his own label creations.
Detail was all important with oversized pointed collars, graphic printed jumpers and more check.
The designer will present his haute couture collection for Dior on Monday.
Around 80 menswear shows are scheduled in Paris over the next five days, drawing to a close on Sunday with the eagerly awaited first Saint Laurent collection by Hedi Slimane, famed for his super-tight, skinny tailoring.
Credited with revolutionising menswear during his seven years at Dior from 2000 to 2007, Slimane teamed jackets cut short with narrow trousers in an androgynous, pencil-thin look so popular even legendary designer Karl Lagerfeld shed 45 kilos (90 pounds) to squeeze into a Slimane suit.