The consumer group Which? is suing the Wigan-based company JJB Sports on behalf of fans who were overcharged for football shirts.
JJB Sports was fined more than £6m in 2003
JJB were fined more than £6m by the Office of Fair Trading (OFT) for fixing the price of England and Manchester United shirts in 2000 and 2001.
Which? is calling for people who bought one of these shirts to register a claim on its website.
JJB Sports says it will not comment until legal proceedings have finished.
The consumer group's online editor Malcolm Coles said: "This case is as much about justice and fairness as anything else.
"We want to teach companies that rip off their customers a lesson."
A case management conference will be held by the Competition Appeals Tribunal to decide how the case will proceed.
JJB Sports was one of a number of companies fined by the OFT in 2003 over football shirt price-fixing.