Gabrielle Bonheur `` Coco '' Chanel ( 19 August 1883 â `` 10 January 1971 ) was French fashion designer . Gabrielle Bonheur `` Coco '' Chanel ( 19 August 1883 â `` 10 January 1971 ) was a pioneering French fashion designer whose modernist philosophy , menswear-inspired fashions , and pursuit of expensive simplicity made her an important figure in 20th-century fashion .