Arafat's widow Suha and his daughter Zawra lodged a murder complaint on July 31 in the Paris suburb of Nanterre. Arafat died at age 75 at a military hospital near Paris in 2004.
"A judicial murder enquiry has been opened, as expected following the complaint from Mrs. Arafat," a source close to the matter told AFP.
Confirming the enquiry, Pierre-Olivier Sur, a lawyer for Arafat's widow and daughter, said they were "happy" at the decision but would not comment further "so as to leave the judges to lead all investigations necessary to find the truth...."
The Palestinian Authority also welcomed the move, with senior Palestinian official Saeb Erakat expressing hope that "we will reach the full truth on Arafat's death and who stands behind it."
"We hope the French investigation will satisfy our desire for truth, and that there will be a serious investigation to reveal the whole truth, in addition to an international investigation to identify all the parties involved in Arafat's martyrdom," he told AFP in Ramallah.