The reclusive designer revolutionized the fashion world in the second half of the 20th century, popularizing the women's trouser suit, making luxury clothes widely available for the first time through his ready-to-wear collections, and becoming the first designer to use black models.
French President Nicolas Sarkozy said on national radio: "One of the greatest names of fashion has disappeared, the first to elevate haute couture to the status of art."
Leading Russian designer Valentin Yudashkin told RIA Novosti: "Saint Laurent gave new life to the idea of haute couture in the 1960s: Christian Dior's favorite student combined in his collections brilliant simplicity, quality, and French chic."
Saint Laurent shot to fame at the age of 21, when he became chief designer at the couture house of Christian Dior after his mentor's death.
However, three years later he was called up for military service in Algeria, where he had grown up. The ordeal drove him to a nervous breakdown that landed him in a psychiatric ward for three months, where he was subjected to electroshock treatment.
His breakthrough to the mass market came amid the massive popular cultural shifts of the 1960s, with sexual liberation, women's unprecedented economic freedom, and the rise of feminism.
As well as women's trousers, Saint Laurent is credited with popularizing safari jackets and thigh-high boots.
Despite being plagued by alcohol and drug abuse problems for much of his life, Saint Laurent's fame grew unabated during the 1960s and 1970s, as Paris cemented its status as the world's fashion capital.
During the latter part of his career, which came to an end in 2002, Saint Laurent suffered ongoing psychiatric and physical health problems, and rarely appeared in public.
The designer's former lover and business partner, Pierre Berge, said in an interview with France Info radio on Monday that Saint Laurent "revolutionized haute couture" but was "someone who was very shy and introverted, who had very few friends and hid himself from the world."
Summing up Saint Laurent's achievements, Berge said: "Chanel gave women freedom. Yves Saint Laurent gave them power."
