Fifa is investigating the transfer payment for Emiliano Sala after Nantes made a claim against Cardiff City.
Premier League side Cardiff were due to pay the first of three instalments for the £15m striker on Wednesday.
Argentine Sala, the Bluebirds’ record signing, died aged 28 in a plane crash in the English Channel on 21 January.
“We can confirm we have received a claim. We are looking into the matter,” said a spokesman for world football’s governing body.
As Sala’s move was an international transfer, it had to go through Fifa’s mandatory system.
The International Transfer Certificate (ITC) was completed but there were issues with the separate matter of Premier League registration.
The ITC was registered with the Football Association of Wales and confirmed Sala as a Cardiff player, which meant the Welsh club were liable to pay Nantes the transfer fee.