Zainab Al-Hilli's state of health is understood to have improved in recent days, allowing her to travel back to the UK.
Zainab left France this morning at around 8am. Police from Britain accompanied the little girl.
Her departure follows that of her younger sister, Zeena, who returned to the UK last week after escaping the brutal attack unscathed. The four-year-old survived by cowering under her mother's skirts but she was only discovered eight hours after the killings.
More top news
Kim Ward has taught Pickles to do tasks such as finding her phone and can even detect when her owner is about to have a seizure.
London Mayor Sadiq Khan is voted sixth most intelligent politician in history, according to a poll
Hollywood star Angelina Jolie Pitt is to become a visiting professor at the London School of Economics (LSE).