Six people have been arrested over a banner, which reportedly attacked Bolton striker Marvin Sordell, police said.
Millwall Football Club refused to comment on the issue, and assistant manager Joe Gallen - who was standing in for Lions manager Kenny Jackett, who missed the game with flu - also chose not to discuss the matter.
A Metropolitan Police spokesman said the arrests were made over alleged public order offences.
– Metropolitan Police spokesmanSix males were arrested during the game at Millwall in relation to a banner being unfurled at the game. They remain in custody at this time."
Six people have been arrested over a banner, which reportedly attacked a footballer who was racially abused by a Millwall fan, police said.
The banner was unfurled in a Millwall section of the Lion's New Den ground during their 2-1 win against Derby County.
Bolton striker Marvin Sordell, was abused by fans while warming up for his side's game at the East London club's stadium on 6 October.
A 13-year-old boy was banned from the ground.