Chelsea paid a transfer fee of €35 million to Lille for the services of Eden Hazard, rather than the €40 million that was originally reported, while the Belgium international received a €2.4 million bonus for being named PFA Premier League Player of the Year in 2015, according to Le Soir.
The Belgian outlet published a series of reports from Football Leaks revealing the financial aspects behind the 25-year-old's contract and his international colleagues.
As well as the fee paid by Chelsea in 2012, Hazard's salary was also leaked; the diminutive playmaker earning €4.71 million in his first season at Stamford Bridge, upping to €5 million in the second year.
Then, when the Belgian signed a new deal in 2015, his pay jumped to €12.5 million a year.
“The first contract of Eden Hazard at Chelsea tells us little," the Le Soir report begins. "Firstly because it dates from 2012 and has since been extended.
"Next because it is less detailed. We discover however that the transfer fee between Lille and Chelsea is not €40m and is instead €35m.
"Aside from that, it also details the star’s gross salary at Chelsea for the first years (4.71 million Euros for the first season and 5 million Euros for the second). But this salary does not represent the reality because Hazard had extended his contract by three years in February 2015 (doubling, according to certain outlets, his salary, going from €5m to €12.4m)."
Hazard's 19 goals in 52 appearances for the Blues during the 2014-15 season helped Chelsea to the Premier League title and earned him the accolade as the best player in the division. As such, he triggered the only clause in his contract - a €2.4 million bonus.
“However," the report continues,"his first contract indicates that there was only one clause that enabled him to win a bonus and that it was quite well chosen because it stipulates that: 'if he is chosen as player of the year, he will earn a bonus of €2.4m.'"
Following a disappointing season last time out, Hazard has struck eight goals in his 14 Premier League appearances this season under new Blues boss Antonio Conte, helping the Blues to the top of the table.
Hazard, who was named Premier League Player of the Month in October, has been described as 'the point of reference' by Conte, who has been impressed with the 25-year-old since his arrival in London.
"I like to see my players always involved in the project when we are playing," Conte previously told a press conference at Cobham Training Centre. "You can see Eden is always involved in the game, not calm and off during the game.
"He always stays in the game and he's always a point of reference for his team-mates. I think he's fantastic for this. It's great for us, for his team-mates to see Eden is always in the right position to receive a pass.