Leinster received a walkover victory on Friday after their European Champions Cup last-16 match with Toulon was cancelled just hours before kick-off because of a positive coronavirus case at the French club.
The controversy left the three-time champions from France furious as their president threatened to pull his club out of future European events.
"We are treated like Kleenex," said Bernard Lemaitre.
In a statement, organisers European Professional Club Rugby (EPCR) said that as Toulon were unable to field a team, the French club had forfeited the game.
"Following medical advice that the match could not be played safely, RC Toulon were unable to select a match day squad after it was deemed that the club had a number of high-risk close contacts with one of its non-travelling players who had tested positive for COVID-19," said EPCR, in a statement.
"Therefore as RC Toulon could not fulfil the fixture, (it was) decided Leinster will progress to the Champions Cup quarter-finals on the weekend of 9/10/11 April."
Before setting off for Ireland, Toulon reported a Covid-19 positive for a front row player who did not travel.
The club said it carried out further tests on Thursday, all of which were negative.
Toulon accused EPCR of "errors" for allowing "the players and staff to travel to Ireland, prepare for the match, only to have them prevented from taking part in this major event a few hours before kick-off."
"The Rugby Club Toulon strongly deplores this decision," the statement said.
Lemaitre had anticipated the verdict in an on-line press conference just before the announcement.
"There is anger and disgust," Lemaitre said.
"I am not at all sure that RCT will re-enter the European Cup."
There was little time for a rearranged match, with the winner due to meet either Lyon or 2020 champions Exeter Chiefs in the quarter-finals next weekend.
Toulon said the organisers had offered to postpone "the match to Sunday on condition that all six front row players", the three starters and three substitutes, were replaced.
But this was a "clear sporting impossibility" said the club.
Earlier, Toulon's veteran Italian forward Sergio Parisse seemed to suggest on Twitter that all French clubs should boycott the competition, writing: "We will see if we ALL show solidarity of not" followed by a French flag and a no-entry sign.
- 'Furious' -
Lemaitre said he thought that unlikely.
"All the players are furious," he said. "But Sergio Parisse's request is not realistic. I've received a lot of nice messages, from the new president of the (French) league and from presidents of the clubs but I don't think I can ask them to boycott the European Cup.
"But it is possible that RCT will do it."
Lemaitre said the trip had cost his club "more than 250,000 euros, with the travel and hotels" and said he was thinking of demanding compensation from EPCR.
This season's competition has been heavily disrupted by the pandemic.
The last two rounds of the pool stage were cancelled in January following French government concerns regarding cross-border travel. The organisers then added a round of 16.
According to EPCR regulations, "if a match cannot be played safely then it will be cancelled, and the club whose COVID-19 status did not compel cancellation will qualify for the next phase."
When Toulon pulled out of a game in December after their opponents, Scarlets, reported a positive test, the EPCR awarded the Welsh side a 28-0 victory.
"This is the second time it's happened to the same club and not just any club. It's a club with a certain reputation, especially in the European Cup. We are treated like Kleenex," said Lemaitre.