Hot on the heels -- literally! -- of H&M's collaboration with Jimmy Choo, the fast fashion retailer has done it again. This Saturday, Sonia Rykiel's collection for the brand -- an extensive line of lingerie, loungewear, and gifts like a velvet rhinestone-embellished pillow and a couple on-trend headbands -- hits 1500 H&M stores worldwide.

The collection was launched last night in (where else?) Paris with a truly spectacular fashion show and party in the historic Grand Palais. The massive venue was transformed into a giant carnival, with sideshow performers, funfair games, and even a ferris wheel with mannequins dressed in Sonia Rykiel designs for H&M riding in every seat.

In lieu of a fashion show, a parade of chauffeured floats, each with models wearing items from both the lingerie and knitwear collections, circling a massive lit-up replica of the Eiffel Tower. With smiling, dancing models and Abba music blaring in the background, the atmosphere was as circus-like as it was chic.

The Sonia Rykiel for H&M collection ranges from $9.95 for a thong panty to $99.95 for a long black velvet dress that could easily go from the lounging around the house to eveningwear. Special occasion items like satin bustiers and bodysuits (that would look great layered under a cardigan) and several sheer black silk pieces with pale rose details that seem (appropriately enough for the holidays) both naughty and nice. The initial offerings will be followed by a bright-and-buoyant range of knitwear for women and little girls that will be available in February.

Earlier today, Natalie Rykiel, Sonia Rykiel's president and artistic director, and H&M creative advisor Margareta van den Bosch, spoke to StyleList about the collaboration. StyleList: How did this collaboration come about?

Margareta van den Bosch: We had been talking about working with Sonia for a while - she's an icon in fashion. We have never made designer underwear, and we wanted to do some gifts for Christmas, so we thought this could be a good project to do with Sonia Rykiel. But to make something with Sonia and make only underwear seemed a little bit too little, and knitwear is what she's most famous for, so we decided to do a second drop in February with a knitwear collection.

SL: Was getting the quality up to Rykiel standards a concern?

Natalie Rykiel: No -- I was very impressed with the quality of the lingerie and the knitwear we did together. Of course it's not the quality of fine cashmere, but it is excellent for the price.

SL: Why are a variety of items along with lingerie included in the collection?

NR: All that is always in the Rykiel universe - there are always pillows and loungewear. And I also wanted to add gifts because for Christmas that is perfect.

SL: Natalie, how would you describe the sensibility behind your designs?

NR: It is the idea of a woman in [the stylish Parisian area] Saint Germain des Prés --- the idea of Left Bank chic. It is an attitude where the woman is more important than the fashion. Being chic is not about wearing high heels: it's an attitude in life.

SL: How will the customers that buy the H&M line differ from the traditional Rykiel customer?

NR: I think some of them will be the same, but I like that people my daughter's age - she's 14 - will also be able to buy these pieces. There are very, very young customers that can buy this, and also people that don't have the money to buy a luxury item but have a pure sense of style.

MvdB: Even if they're girlish and playful, I think the pieces can also work for more mature women.

SL: Although this year has seen partnerships with Matthew Williamson and Jimmy Choo, H&M does less designer collaborations than retailers like Target. Why?

MvdB: We can't do it all in time. It must be something special, and we also have over 100 in-house designers that make new collections all the time. I think it would disturb our own collections to have [design collaborations] too often.

SL: Do you feel that last night's event was a success?

NR: It was like making a dream come true. It was like being a child for one night.

SL: Natalie, are you an H&M shopper?

NR: My daughters are. I hate the crowds.