This comes just days after wreckage from the plane carrying Cardiff City footballer was discovered in the English Channel with a body which is yet recovered.
An underwater camera showed one occupant was visible in the wreckage.
BBC's report adds that Nantes are threatening legal action if they do not receive a payment from Cardiff within 10 days.
Cardiff will honour the deal but not until they have clarified "all the facts".
However, British air accident investigators have yet to say whether the body was that of Sala, who had just signed for Premier League club Cardiff, or pilot David Ibbotson. BBC have attempted to speak to Nantes for a comment.
Ice pellets and freezing rain could impact Wednesday's commute
This means that "highways, roads, walkways and parking lots" are likely going to become icy and inevitably unsafe and slippery. We see a break from precipitation much of Wednesday before the next approaching area of low pressure arrives Thursday.
The 28-year-old was on his way back to Cardiff from Nantes after saying his goodbyes to his old team-mates in France.
The agreement reached by Nantes and Cardiff was that the Premier League club would pay the £15 million fee in instalments over three years.
In a statement, the Air Accidents Investigation Branch (AAIB) said: "Following extensive visual examination of the accident site using the remotely operated vehicle (ROV), it was chose to attempt recovery operations".
It continued: 'Unfortunately, attempts to recover the aircraft wreckage were unsuccessful before poor weather conditions forced us to return the ROV to the ship.
Remotely operated Vehicles (ROVs) were used in "challenging conditions" to pull the body out of the water "in as dignified a way as possible" the Air Accidents Investigation Branch (AAIB) said on Wednesday night.