Neymar, the world's most expensive football player, has attended a Spanish court accused of fraud and corruption over his transfer to Barcelona from Santos in 2013.

The current Paris Saint-Germain forward faces charges along with eight other defendants that include his parents, two former FC Barca presidents and Odilio Rodrigues, the former president of Brazilian club Santos.

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The trial centers around Brazilian Company DIS, which owned 40 percent of the player's transfer fee when he was at Santos. 

They claim only to have received a fraction of the actual income they were due when Neymar moved from Santos to Barca in 2013.

Barcelona said the transfer cost $56 million, but prosecutors believe it was at least $81 million. It is alleged that both football clubs and Neymar's family colluded to reduce the market value of the transfer as other clubs could have offered more.

Neymar had always stated that Barcelona was his club of choice and not the highest bidder.

The defense stated: "The free rules of competition don't operate in the transfer market between clubs, as a transfer depends on the free will of the player."

In addition, they say that the Spanish courts have no jurisdiction as Neymar's family are from Brazil and the transfer involved Brazilian nationals, living in that country.

Third-party ownership

The practice of third-party ownership of footballers has been common in South America, where management companies buy a percentage right to the value of a player, and it is an area that has suffered from a lack of transparency.

Juan Castro, journalist at Spain's Marca newspaper, told CGTN Europe that there is a lot to learn from the Neymar court case. 

"I think a lot of people will learn from this, not only Neymar. Little-by-little transfers are becoming more transparent," he said.

"Even the transfer bonuses for the players, for example, when Kylian Mbappe renewed his contract with PSG, the club revealed his bonus was over 100 million euros ($98 million).

"Players making individual mistakes helps the industry to learn, as a whole."

The prosecution is seeking a two-year jail term for Neymar and a $10 million fine. Along with this, they are pushing for a five-year jail sentence for the former Barcelona president Sandro Rosell and an $8 million fine for Barcelona FC. 

All defendants have denied the charges.

The trial is set to run until the end of the month, just three weeks before Neymar will represent Brazil at the World Cup in Qatar.