The Rugby Football League has issued Catalans Dragons with an advisory notice after the club asked a fan to remove a rainbow flag during a game.
The incident occurred in a Super League game against Castleford on 15 February.
Catalans say the request was made because the flag covered an advertising hoarding at Stade Gilbert Brutus.
The French club has been advised to improve provisions “to prevent any future confusion around policies relating to any flags at the stadium”.
No formal disciplinary action has been taken against the Dragons.
Former dual-code Australia international Israel Folau was making his debut for the Perpignan-based outfit during the match against the Tigers.
It was his first competitive appearance since the 30-year-old utility back was sacked by Rugby Australia in May 2019 for posting homophobic comments on social media.
The RFL investigated the matter, with full co-operation from Catalans, and found “sufficient footage” which showed two supporters had been permitted to bring rainbow flags – a symbol of LGBT pride – into the ground and to wave them during the game.
The RFL has also asked Catalans to give clear messages to stewards about the club’s policy on flags, and the club’s and the sport’s commitment to inclusivity.
This includes the Enjoy the Game campaign – which promotes encouraging environments throughout rugby league – and the right for spectators to respectfully promote inclusion.
Catalans thanked the RFL for their investigation into the mater.
“It is has been clearly established one supporter breached the stadium code of conduct by covering one of club’s advertising boards, and that one stadium steward correctly ask[ed] him to stop it covering the board,” a statement on the club website said.
“The club also thanks the RFL for confirming that the two supporters were clearly shown displaying their flags throughout the game, with no-one from the stadium security preventing them from waving their flags.
“We will continue to make sure our stadium policy is clear for everyone.”
Meanwhile, Hull FC has confirmed to BBC Sport they will allow supporters’ flags when they host Catalans on Sunday (15:00 GMT).