Borussia Dortmund have fined Pierre-Emerick Aubameyang for his masked celebration in the 1-1 derby draw at Schalke on Saturday, with the club telling ESPN FC: "We've had a good talk with Auba."
Aubameyang, 27, opened the scoring at the weekend and celebrated by putting on a mask, later identified as being part of Nike's "The Masked Finisher" campaign.
It was the second time in less than a month that the Gabon international has promoted the sponsor while playing for Dortmund, where rival sportswear company Puma is both a shareholder and the kit supplier.
"We've had a good talk with Auba," Dortmund media director Sascha Fligge told ESPN FC afterwards.
Dortmund sporting director Michael Zorc confirmed to kicker that the club have fined Aubameyang for his masked celebration, though he did not disclose the amount of the sanction.
"He wasn't aware of the consequences of his actions," Zorc said. "[But] we couldn't tolerate it."
Meanwhile, Aubameyang's brother Willy posted a picture of him wearing the mask with the striker sitting next to him.
A post shared by Willy.Aubameyang (@willy.aubameyang) on
It remains unclear when the photo was taken, and Fligge played down the post, saying: "I don't even know the brother."
Elsewhere, kicker reported on Thursday that Dortmund and Shinji Kagawa have yet to enter talks about a new contract, with the midfielder's current deal expiring in 2018.