The case has regenerated debate in Japan, where shared custody is not legally recognised and children are often "abducted" by one parent.
France has issued an arrest warrant for a Japanese mother accused of abducting two children from their father.
Vincent Fichot says his wife disappeared with his now 6-year-old son and 4-year-old daughter in Tokyo three years ago.
On Tuesday, the French justice system issued an arrest warrant for the abduction and endangerment of a minor, according to AFP.
Fichot had originally filed a criminal complaint against his Japanese wife in 2019.
The former finance worker generated media attention for his case by going on hunger strike for three weeks this summer during the Tokyo Olympic Games.
His action has sparked debate about so-called "parental kidnappings" in Japan, where shared custody is not legally recognised. Local Japanese authorities often accept parental abductions when a mother and father separate.
French President Emmanuel Macron, who visited the opening ceremony of the Olympics, also raised Fichot's case with the Japanese government.
The French father says he hopes the arrest warrant will influence an upcoming court decision on the children's custody.
"How can a Japanese judge award custody to a mother who is wanted internationally?" Fichot said, adding that he still wanted joint custody.
A lawyer for his Japanese wife told AFP that "divorce proceedings are underway".
"We have no intention of fighting outside the court," Hatsuko Tsuyuki said, refusing to comment on the arrest warrant.