Atletico Madrid have reportedly claimed that an email sent by the lawyer of Antoine Griezmann in March proves that Barcelona should have paid £184m for the Frenchman.
Griezmann finally completed a move to Camp Nou earlier this summer after Barcelona agreed to pay the forward's £108m release clause.
However, it is claimed by Atletico that since Barcelona commenced negotiations for the 28-year-old in March, they are owed another £71.8m due to a previous clause in his contract.
According to El Mundo, the publication holds an email from Griezmann's representatives - sent to the player's sister and father - containing an offer from Barcelona which proves that the La Liga champions did indeed begin their pursuit in March.
The email, originally sent by Griezmann's lawyer Sevan Karian, is said to also contain a draft of salary proposals.
In response, Barcelona have insisted that the email does not imply any evidence of direct negotiations with Atletico because it was not sent to a club employee.
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