French authorities are using helicopters, diver teams and sniffer dogs to look for the woman in her sixties.
“The helicopter has flown along the Rhône to the sea for the possibility that we see a floating body there,” said a spokesperson for the French police.
Shortly after her disappearance, her husband, 66, was stabbed in the hands, abdomen and neck by a man he described as being between the ages of 40 and 50. The husband is currently recovering in hospital in Arles.
The bizarre attack happened shortly after noon Thursday near the commune of Tarascon, 20 kilometres south of Avignon. The couple was vacationing in the area when they paused at a rest stop. When the wife didn't return, the husband went to look for her when he found blood on the steps leading to the river bank. It was then that he was attacked.
No further details on the couple or their alleged attacker have been released.