Crystal Palace have been fined by the Premier League over an allegation that information regarding the Cardiff line-up prior to the sides' encounter in Wales last season was leaked to the London side.
The Premier League board upheld a complaint from Cardiff, who alleged that team information was leaked to officials at Palace prior to the match on April 5.
"The Premier League board has considered a complaint from Cardiff City regarding the conduct of a Crystal Palace official," a statement from the League read.
"The board found that Crystal Palace breached Rule B.16 and has exercised its summary jurisdiction and fined the club."
Rule B.16 states that "in all matters and transactions relating to the League each club shall behave towards each other club and the league with the utmost good faith".
With both teams battling to stay in the Premier League, Palace won the game in Cardiff 3-0. Palace could face a fine of up to £25,000.
Cardiff had no comment to make on the matter.
Palace declined to comment on the Premier League's decision and said they would not be issuing a statement.
At the time of the incident, Cardiff submitted an official complaint surrounding the alleged leaking of their team.
Palace sporting director Iain Moody worked for Cardiff until earlier last season before taking up a post at Selhurst Park in November.
It was reported that Cardiff believed Moody might have used his contacts at the Welsh club, or close to Cardiff, to find out which players would start against Palace.
Moody rejected the allegations as "incredibly, extraordinarily untrue" and Palace also denied the claims.
Tony Pulis, who until the end of last week had been the Eagles boss, insisted at the time that Palace had not acted inappropriately and that Cardiff's team selection had not entered his thinking.
"If we have to go up and meet the Premier League, or whoever it is that we have to meet, then we'll do it in the right and proper manner. We won't do it any other way, and I think that is important," Pulis said.
"As a manager and as a coach, I log every session that I do, and I'll be taking those sessions up to the Premier League to show that I picked my team on Monday before we played Cardiff on the Saturday.
"That team was worked with for a week and there were no changes in it whatsoever."