The Rugby Football Union has decided not to take any action against Leicester director of rugby Richard Cockerill or coach Matt O'Connor.
The pair were alleged to have abused match officials during last weekend's 11-3 Premiership play-off semi-final win against Northampton.
They were also accused of making remarks about referee Wayne Barnes to his assessor, Brian Campsall.
Cockerill denied using foul or abusive language, saying he was not aggressive.
The main flashpoint in the game was Manu Tuilagi's much-publicised punching of Northampton's England winger Chris Ashton, for which the Tigers centre received a five-week ban, ruling him out of Saturday's Premiership final against Saracens.
But, following the match, the RFU received a "small number of e-mail complaints alleging foul-mouth abuse and ranting" and this, as well as reports which appeared in the press, caused them to launch an investigation.
The investigation, which also took evidence from Leicester Tigers executive director Peter Wheeler and head of rugby operations Simon Cohen, included a copy of the commentary of the game, supplied by BBC Radio Northampton.
But, having listened to the commentary, the RFU statement read: "The only discernible comment made by Richard Cockerill is 'He's meant to be a Test referee. In the biggest match of the season. It's not bloody good enough. Yellow card'.
"The only direct evidence suggests that they were both voluble in their support and advice throughout the game, and there was clearly recorded criticism of a refereeing decision not to award a yellow card at some stage in the match.
"On the evidence there is nothing which suggests that any of this was prejudicial to the interests of the game."
Match assessor Campsall also telephoned the RFU after the game to say he had been questioned by a reporter about the behaviour of Cockerill and O'Connor.
But, in a statement to the RFU, Campsall said: "I was not aware of what was said by any individual due to the intensity of the game.
"I was too busy writing in my notebook during this game, as well as listening to the match officials to notice anything that was being said by coaches from either team."
Campsall added that he did "catch the eye of Cockerill" on one occasion and acknowledged his comment with a raised hand, but "could not tell what he was saying because of the crowd noise."