Miss goldenweek was a member of Baroque works. She hasn´t got devil fruit´s powers.
She has control on the Colors trap she can hypnotizes her victim through the influence of colours and can alter a fight accordingly. Her attacks are:
-Uragirimono No Kuro (Black - Color of Betrayal): Causes target to do the opposite of what is said. Orginally used against Luffy. She later uses against some Marines in the Mini-Story Miss Goldenweek's Operation "Meet Baroque Works". 
-Warai No Kiiro (Yellow - Color of laughter): Causes target to laugh uncontrollably
-Tougyuu No Aka (Red - Color of a Target): Causes target to always attack where the mark is painted.
-Kanashimi No Ao (Blue - Color of Sadness): Makes the target to be sad. Not seen.
-Nagomi No Midori (Green - Color of Soothing) (Blue + Yellow): Causes target to sit down and have a picnic with Goldenweek.
-Shinboku No Kiao (Yellow-Green - Color of Friendship) (Green + Yellow): Causes target to be Goldenweek's friend and help her out.
-Yume No Niji (Rainbow - Color of Dreams): Effect is still unknown, but it apparently makes anyone who sees it realize their dreams, and change their appearance to match it.
She was defeated by Carue, Vivi's pet spot-billed duck.
She with the help of Mr.5 and Miss valentine rescues the rest of baroque wors´members unless Crocodile, Mr.1, Mr.3 and Mr.2.
Her dream is become a true artist, complete with a beret and mustache.