Queen of Knitwear Sonia Rykiel died on August 25 at the age of 86.
The French fashion designer had been suffering from Parkinson’s disease for some time before her death.
Her daughter, Nathalie Rykiel, said: “My mother died at 05:00 this morning at her home in Paris from the effects of Parkinson’s.”
Nathalie Rykiel is also the managing and artistic director of the Sonia Rykiel fashion label.
French President Francois Hollande praised Sonia Rykiel as “a pioneer”.
Francois Hollande said of Sonia Rykiel, whose relaxed striped knitwear was seen as a shift away from more formal suits: “She invented not just a style but an attitude, a way of living and being, and offered a freedom of movement.”
Jean-Marc Loubier, chairman and chief executive of First Heritage Brands, the parent company of the Sonia Rykiel label, said: “It is a sad day but Sonia Rykiel leaves behind her an extraordinary legacy.”
He added that she had “helped women and society evolve.”
Sonia Rykiel was born Sonia Flis in Paris in May 1930, to a Romanian father and Russian mother.
She started her career as a window dresser in 1948, with her first foray into design being when she knitted herself maternity dresses after marrying Sam Rykiel, the owner of a Paris boutique.
Sonia Rykiel made her breakthrough in 1962 with the so-called poor boy sweater, which had long sleeves and a fitted shape.
Elle magazine then featured teenage pop star Francoise Hardy wearing a red and pink striped Rykiel sweater on its cover in December 1963.
Brigitte Bardot was later photographed in a Rykiel creation, with Audrey Hepburn among her other famous fans.
Sonia Rykiel opened her first ready-to-wear store on Paris’s Left Bank in 1968 and her fashion empire went on to include menswear, children’s clothing, accessories and perfumes.
According to her website, Sonia Rykiel “urged women to be eccentric, seductive, mysterious, and to create their own style”.
During her career Sonia Rykiel developed new techniques like inside-out stitching and no-hem finishings, with other star pieces including embroidered knitted tops and rhinestone-studded berets.
Sonia Rykiel wrote several novels and also featured in 1994 movie Pret-a-Porter, Robert Altman’s satirical take on the fashion industry.
In 2012, she revealed she had been diagnosed with Parkinson’s 15 years earlier.
The designer had initially kept the condition private but wrote about her diagnosis in a book when her symptoms became too difficult to disguise, fashion site WWD said.
Sonia Rykiel is survived by her daughter Nathalie and son Jean-Philippe.