From 2005 to 2009, Flight Centre tried to get airlines to charge customers more on their own websites than the fares offered through the travel agency.
"Lowest Airfares guaranteed" indeed.
Today it has been ordered to pay penalties totalling $12.5 million by the Full Federal Court of Australia.
Three international airlines were approached by Flight Centre and asked to enter into price fixing arrangements - Singapore Airlines, Malaysia Airlines and Emirates.
According to the ACCC, who first took the matter to court, the $12.5 million in penalties imposed today is an increase from the original $11 million imposed on Flight Centre by the trial judge in March 2014.
"The ACCC appealed from the initial $11m penalty orders because it considered that this level of penalty was inadequate to achieve a strong deterrence message for Flight Centre and other businesses," ACCC Chairman Rod Sims said.
"Flight Centre is Australia's largest travel agency, with $2.6b in annual revenue. We will continue to argue for stronger penalties which we consider better reflect the size of the company, as well as the economic impact and seriousness of the conduct. Significant, large penalties act also as a general deterrent to other businesses that may be considering such conduct themselves."
Sims says the ACCC wants to ensure that penalties for breaches of competition laws are not seen as "an acceptable cost of doing business".
Here's how it all went down: