Tottenham have banned three fans indefinitely after they tried selling their Champions League final tickets online.
Spurs, who face Premier League rivals Liverpool in the final in Madrid on June 1, have also issued a warning to other fans doing the same.
"Once again, we wish to remind all our supporters that any ticket purchased is for the sole use of the individual that purchases it from the club," a statement from the club said.
"Transferring or selling tickets on unofficially breaches our terms and conditions and is against the law.
"We shall look to take the strongest possible action against anyone found to be engaging in such activity - including indefinite season ticket bans."
Spurs will be targeting a first Champions League title in their history.