Nantes have requested the transfer fee for Cardiff striker Emiliano Sala, who is missing presumed dead after a plane crash, according to BBC Sport.
City bought the forward for a club-record fee of £15 million ($19m) in January only for the player's plane to disappear in mysterious circumstances.
It has since been found but no bodies have been identified.
BBC Wales reports that the transfer fee was originally scheduled to be paid in a series of installments over three years.
Cardiff have yet to send the first payment, as the club reportedly awaits more facts from the crash investigation to arise. Nantes have threatened legal action.
Bordeuax - Sala's club from 2012 to 2015 - also have a stake in the pending legal proceedings, as the club are owed a sell-on fee (reportedly a full 50%) after the striker's planned move to the Premier League.