MARSEILLES, France (Reuters) - A French psychiatrist whose patient hacked an elderly man to death was found guilty of manslaughter on Tuesday in a groundbreaking case that could affect the way patients are treated.

              A court in Marseilles said Daniele Canarelli, 58, had committed a "grave error" by failing to recognize the public danger posed by Joel Gaillard, her patient of four years.

              Gaillard hacked to death 80-year-old Germain Trabuc with an axe in March 2004 in Gap, in the Alps region of southeastern France, 20 days after fleeing a consultation with Canarelli at Marseilles's Edouard Toulouse hospital.

              Canarelli was handed a one-year prison sentence and ordered to pay 8,500 euros to the victim's children, in the first case of its kind in France. Defense lawyers said the ruling would have serious repercussions for treatment of the mentally ill.

              "If a psychiatrist lives in fear of being sentenced, it will have very real consequences and probably lead to harsher treatment of patients," said Canarelli's lawyer, Sylvain Pontier.

              The court said Canarelli should have requested Gaillard be placed in a specialized medical unit or referred him to another medical team, as one of her colleagues suggested. Her stubborn refusal had equated to a form of "blindness", the court president Fabrice Castoldi said.

              Gaillard had already been forcibly committed to a secure hospital on several occasions for a series of increasingly dangerous incidents.

              The victim's son, Michel Trabuc, said he hoped the case would set a legal precedent.

              "There's no such thing as zero risk, but I hope this will move psychiatry forward and, above all, that it will never happen again," he said.

              Gaillard was not held responsible for his actions and was freed under medical supervision.