A person with knowledge of the case says Nantes has filed a formal claim with FIFA against Cardiff to start collecting the transfer fee for Emiliano Sala.
The person says the French club wants Cardiff to pay the first installment of the transfer fee. The person spoke on condition of anonymity because the person was not authorised to speak publicly on the matter.
FIFA says it received "a claim from FC Nantes against Cardiff City in connection with the transfer."
Sala, an Argentine striker born in Progreso, Santa Fe provoince, was killed last month before ever playing a match in the Premier League. The single-engine aircraft with Sala and pilot David Ibbotson on board crashed in the English Channel while flying from Nantes to Cardiff.
Nantes and Cardiff are in a dispute over the 15 million pound (about US$20 million) transfer fee the Premier League club agreed to pay for its record signing.
Cardiff officials have said they are "gathering information" on the circumstances of the accident.