Three victims, including a 13-year-old child, were treated at hospital.
The adults were taken to Nice University Hospital (CHU) with serious injuries, while the child with minor injuries was admitted to Renval Children’s Hospital in Nice in non-critical condition.
On Wednesday, the man was no longer in a life-or-death situation, but the woman’s condition was not yet stable, AFP reported.
Monaco authorities did not confirm the identity of the victims, but local reports said the attack targeted Vadim Yermolyev, his partner and his son.
Yermolaiev, 58, is a wealthy real estate developer living in Monaco. He is a Cypriot citizen after renounced his Ukrainian citizenship in 2019.
He has a keen interest in the wine and spirits business in the Russian-annexed Crimea peninsula, which has been subject to sanctions imposed by the Kiev government since 2023.
He was ranked the 39th richest person in Ukraine by Forbes magazine in 2020, with a fortune of $230 million (£173.8m).
