Mont Blanc Wallets was bound to happen given all the routine encounters

It has been fondled by Tom Ford, turned over and admired by Miuccia Prada and now — Mont Blanc Wallets was bound to happen given all the routine encounters — this writer’s little black bag has been copied by Marc Jacobs for Louis Vuitton.

Salvatore Ferragamo, the maker of the year-old clutch bag with a turn-lock closure in stainless steel, ought to demand royalties. When Mr. Jacobs said in a note that he had been inspired by Designer Replica Handbags when he saw it backstage last month at his own show in New York, one wondered if he would actually produce something like it for Vuitton. And he did — not an exact copy; he fudged a few details. But the similarities were there, and there was nothing flattering or amusing about it.

In this business, and perhaps in art and music as well, you aren’t supposed to take copying seriously, because it’s rampant. Everyone does it. And because of the commercial pressures on designers like Mr. Jacobs to produce several Louis Vuitton Wallets collections a year, the ways in which they lift ideas have become as ingenious as they are sly.

Take for instance the maribou pompoms that appeared as sex-pot adornment on chaste wool coats in Mr. Jacobs’s show today, and on shoes in Christian Lacroix’s collection on Sunday. Just how did those two wildly different designers happen to latch onto something as offbeat as pompoms? By looking to someone in the margins of fashion — most likely, Yvan Mispelaere, the designer at Féraud. His Balenciaga Handbags collections of the last two seasons were so loaded with girlish frippery, like button embroidery and round Peter Pan collars, that they were quickly dismissed as amateur.

But that’s how fashion works today. A design assistant, with connections to stylists and photographers, picks up on a new style and takes it back to the mother ship — namely, the big luxury houses that have to churn out lots of Balenciaga Wallets.

Many of Mr. Jacobs’s Empire dresses and coats, scattered with buttons or sweetened with rippling collars, looked great, especially if you don’t know or mind that the silhouette is an old Patou one that Mr. Mispelaere was toying around with six months ago. As for Mr. Lacroix, his Replica Louis Vuitton Handbags show was such a confusion of some truly marvelous gems, like a shirtdress lacquered with square ruby paillettes, and some atrocious examples of bad taste (a video of a woman wearing pasties and writhing a good deal played in the background) that it was just hard to follow.

With so much casual lifting — even the inventive Dutch team of Viktor & Rolf depended on the silhouettes of Chanel and Yves Saint Laurent to pull off their brilliant conceptual show Saturday — the French fall Replica Louis Vuitton collections have hit a snag. At least Rei Kawakubo of Comme des Gar?ons kept her head on, proving with naughty slip dresses, flaring crinolines and conical bra tops strapped over manly jackets that she can take apart the current obsession for underpinnings, and still say something new.

Jurgi Persoons’s presentation was held Friday night next to a couple of motor coaches parked in the subterranean garage of the Pompidou Center, where a Pop Art retrospective sponsored by Yves Saint Laurent and Gucci opens Tuesday night with the usual supersmooth crowd bussing everyone in sight. Being in the basement has its symbolic meaning — one must start somewhere — as well its aesthetic value. Mr. Persoons’s Louis Vuitton Handbags, worn by models lying like cadavers on 18 separate slanting mirrors, are for fashion’s underground.

Rough around the edges, in humble fabrics like cotton and wool herringbone, they are for people in flight from the banality of brand culture. Yet, despite his moody colors and inert models, Mr. Persoons is no rebel sad sack. Full skirts, including one blossoming with starchy rows of Replica Handbags, suggest an oddball exuberance that was quieted by a plain cotton shirt. Mr. Persoons is Belgian and shares with lowland masters a taste for frumpy severity. But caught in the reflection of the mirrors was a gridlock of girders, an ingenious way for a young designer to evoke the modern horizon.