As the curtains were closed at the Palais d'Iéna for the last blockbuster show of the season, you knew something special was about to happen. For starters, there were curtains at the windows—something never experienced before at this venue, a place that is usually bathed in natural light. There was also a complex wooden set designed by Rem Koolhaas' OMA. Merely the evidence that Miu Miu had cut through such a massive amount of French bureaucracy—this is a government-affiliated building—showed that the label meant business. These are the pyrotechnics usually reserved for Prada shows.

The dark setting, the smoky lighting, the jazz trumpet opening, featuring snatches of "Miles and Miles of Miles Davis" by Malcolm McLaren—it was the kind of ambience usually reserved for a French femme fatale of the fifties. And the first looks? All dark denim.

That dark denim was one of those simple statements Miuccia Prada presents that just has a strangely profound resonance for a collection. The shapes might have been those of fifties couture classics, but that dark denim was the contemporary touch of a contemporary house. But to add to the perversity, "All of the denim was lined in duchesse satin," the designer explained after her show, with some glee. That is, after all, the quintessential couture fabric, relegated here to a mere—very expensive—lining; a decadent motif in the extreme. "I was trying to be very elegant in a very different way," Prada continued. "It was not about destroying elegance, but achieving a different kind. There was a mixture of the rich and the poor fabrics, a manipulation of fabric and material to mean something else." She added: "The femme fatale is never perfect…at least the ones I like."

What Miuccia Prada presented today was about the opposite of perfection. Grand yet effortless, and with ease—that ease, again, that is on the side of the slattern this season. This was a workwear femme fatale, with a hands-on dishabille wardrobe: Furs were tie-dyed and casually slung over shoulders, or they were vast; evening coats that were oversize, creased, and crumpled—this time in that characteristic duchesse satin—were given the same tie-dyed treatment, almost appearing like massive stains. It was a contemporary updating of the kind of clothes Simone Signoret might sashay around in. She was, after all, often typecast as a good-time girl.

At the same time, this was not a retro collection; the layering of history in those rich and poor fabrics was used to arrive at the point of today. Like the music of the presentation, it was a sampling that showed the way to something else. Malcolm McLaren's reworking of Erik Satie's "Gnossienne No. 3" through the eyes of Miles Davis, spliced alongside Neneh Cherry's version of Cole Porter's "I've Got You Under My Skin"? As Miuccia Prada is oft likely to say: It's complicated. Like McLaren himself, she is a kind of big-business punk impresario. And while she might change her style, her signature always remains the same. The ideas may be complex, but this is her unerring knack: She always makes it look easy.