Baby's Got Back

Riddle: My first is a negative greatly in use, By which people begin when they mean to refuse; My second is Fashion, or so called in France, But, like other whims, is the servant of chance. An article always in use is my whole, With texture and form under fashion's control; But, alas! not a thing can it see which goes by, Although many have four sights, and all have one eye. What am I?