Bayern Munich stars Bastian Schweinsteiger and Toni Kroos have been fined by the club for wearing the wrong socks, according to reports.
Bild claims the two Germany internationals were punished for wearing the incorrect kit during a training session at the Bundesliga leaders' winter camp in Qatar. They were reported to have been wearing white socks instead of the black worn by the rest of the team.
"We have a common goal," head coach Jupp Heyncks was quoted as saying. "We need discipline. It starts with everyone wearing the same socks."
Club captain Philipp Lahm was asked to determine the size of the fine and collect the money, Bild reported.
Bayern chief Karl-Heinz Rummenigge backed Heynckes's decision, adding: "I like the way the coach acts."
Heynckes, whose current Bayern contract expires in the summer, has yet to open talks over a new deal.
"I will not change the way I work, no matter what will happen in the summer," he said.
The Bavarian club finished in second place in the Bundesliga, German Cup and Champions League last season, but are nine points clear at the top of the league this term.
They resume their domestic campaign at struggling Greuther Furth on Saturday January 19.