“Yo, check this out. I was looking at this old picture of Big L, and these archive Raf Simons photos, and I was like…no fucking way.”

“That’s jokes.”

“So jokes, right?! We had to photoshop his head a bit but we made it work.”

I’m in Paris, and 424 founder and designer Guillermo Andrade is cracking up as he shows me a T-shirt he designed for his FW17 collection. He's taken a grainy, black-and-white image from an old Raf Simons campaign, removed the model, and spliced in a photo of Big L. The tee is hilarious, and the perfect metaphor for streetwear's relationship with high fashion: it doesn't matter what the rules are, just take what you like and make it yours.

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Elsewhere in 424’s showroom are a pair of leather boots that have been embossed with red and black paisley. They wouldn’t look out of place on a Dior runway, but they're also a sly wink at LA gang culture. There's also a hoodie that's had a 424 logo embroidered onto it, GAP style, before it's been delicately hand-plucked from the bottom half down by Japanese craftsmen. It costs around $600. Guillermo has no formal fashion training, no corporate backing and no ateliers on-hand to produce his clothing, but that hasn’t stopped him from mining high fashion for ideas.

As I leave for my next appointment he yells at me across the room, in his thick LA drawl. “West Coast gang culture, Japanese hoodies, fancy-ass shoes!”

Later that same day, I'm being given a tour of the Givenchy showroom. It’s a sterile, all-white, Gattaca-esque space, located in a stunning Parisian boulevard with an equally spectacular view of the Seine. An army of helpers, head-to-toe in black suits, are running around getting coffees for the buyers hunched over laptops placing their FW17 orders.

In among all the bejeweled suits and cashmere coats is a rail filled with what the PR refers to as the house's “commercial collection” — hoodies, track jackets and the like. He tells me how it’s important for Givenchy to produce these sorts of pieces, because streetwear is “part of the house’s DNA.” Givenchy, a 65-year-old Parisian couture house, has streetwear in its DNA now.

Later in the week, I’m sitting at the Hermes show. There’s more guys in black suits, but this time they’re handing out glasses of champagne. Some pretty tame rock music — the sort of thing your dad listens to — plays from the stereo at a completely acceptable volume, and a bunch of pretty boys march out wearing clothes that your dad would probably be into, too. In among all the nice suits, nice shirts and nice trousers, is an oversized leather waistpack.

In America, it’s the sort of thing you’d associate with aging tourists as they fumble with selfie sticks somewhere in Europe. On the streets of London, Paris, Amsterdam and Berlin, though, it’s the roadman bag: something inner-city guys use to stash their lighter and rolling papers. Hermes, makers of the most expensive clothing on planet earth, the house that, if you have enough money, will upholster your private jet in crocodile skin, makes roadman bags.

Meanwhile, the dad caps Demna Gvasalia designed ("designed") for Balenciaga are all the rage on the fashion week circuit. The almost 100-year-old Parisian couture house makes must-have baseball caps that look exactly like the ones Polo has been doing for decades, but they say Balenciaga on them and cost ten times the price.

Of course, there's nothing new to this sort of thing. Fashion houses have been producing really expensive streetwear for years, and the opposite has been happening since Dapper Dan was creating pseudo-luxe pieces for rappers in the ’80s. The two worlds have been bleeding into each other for ages, but last month's Paris Fashion Week completely obliterated the final brick in the wall separating the street from the catwalk.

The opening look of Louis Vuitton's FW17 show — Noah Brown in a tailored suit, silk shirt and bright red Supreme bag slung across his shoulders — was a gunshot signal that the two worlds are now one and the same. The last time Supreme referenced Louis Vuitton they ended up staring down the barrel of a cease and desist, and now the two are officially collaborating. You'll soon be able to buy Supreme from Louis Vuitton stores. It's nuts.

Looking around the rest of the FW17 collections in Paris, I got the overwhelming impression that streetwear is the only style that matters anymore. The big houses still do tailoring, of course — rich old guys always want suits — but they're styling it out to make it look street, young, and now. Even Thom Browne, the lord of grey suits, makes sneakers and sweatpants. Meanwhile, every up-and-coming streetwear designer is obsessed with Raf Simons. Highsnobiety readers are just as happy talking about Margiela, Rick and Raf as they are Supreme, Stussy and BAPE.

Of course, it's important to not confuse all this expensive luxury stuff with high fashion. "Right now we define a lot of things as high fashion, but they’re not" Raf recently told GQ. "They’re clothes on the runway with a nice little twist of styling and coloration. Everybody thinks it’s high fashion. Bullshit." The really expensive stuff sitting on the floors of department stores is more often than not just beautifully-crafted versions of the same old wardrobe staples.

On the final day of my stay in Paris, I pass by the Cartier store on the Champs-Élysées. I go to the door, but it won't open. I look up, and there's two guys holding it shut. They point to my hoodie and track pants, shaking their heads. The message is pretty clear: you're not welcome here. That very same day, Guillermo opens up the 424 showroom to the public, giving streetwear fans the chance to hang out, touch the clothes, and see what's coming in six months' time.

The grand unveiling of Supreme x Louis Vuitton was the ~fashion moment~ that signified the end of an era. Now, the only difference between streetwear and luxury fashion is in the fine print: where it's made, where it's sold, what it costs. If you want a cotton sweatshirt with a graphic on it, you can find one from Stussy ($70) or Givenchy ($790). Plain white sneaker? Reebok has got your back ($75), but so does Saint Laurent ($595).

It doesn’t matter if it's coming from a centuries-old luxury house that's owned by a billion-dollar conglomerate, or a couple of guys from the West Coast who love rap and Raf, the style is basically the same.

And you know what the best thing is? The guys from LA are doing it better.