Wales coach Rob Howley is still fuming over a controversial substitution and biting allegations during his team's last-gasp 20-18 defeat by France in Paris.
France scored a try 20 minutes after the end of normal time to seal victory after a bizarre end to the game.
Howley said replacement prop Uini Atonio's substitution by starter Rabah Slimani in stoppage time was unlawful and that there was evidence Welsh winger George North had been bitten.
"The integrity of the game has been brought into disrepute," Howley said. "What happened in the last moments of that game shouldn't ever happen again. One of the coaches had a word with their doctor and within a minute of that their tighthead went off. The evidence suggests that it's not in the integrity of our game."
Slimani had earlier been replaced but he was allowed back on when Atonio went off for a head injury assessment.
Howley believes the substitution was planned, suggesting that Slimani should not have been allowed to come on again.
"Slimani warming up prior to him going back on. One of their coaches outside the technical area had a conversation with the doctor, and within a minute of it, the tighthead was taken off," Howley added.
"There is a technical area and you are not allowed outside that. Ultimately, someone has come outside that and allowed the doctor to go on at a break in play, which is outside the laws of the game."
Asked whether France had cheated, Wales captain Alun Wyn Jones said: "I would not use that word but I think there will have to be someone looking at it."
France coach Guy Noves said his team had followed due process. "They told me he was injured so I took my responsibilities.
North even claimed that he was bitten during the closing stages of the match. "It's gone to the TMO (television match official). The evidence was inconclusive in terms of the images that were shown to the referees and ultimately they've made a decision on that and it's absolutely fine," Howley said.
"I am sure you can ask George if you can have a look at his arm. There is evidence to suggest that there is a bite."
Meanwhile, France lock Yoann Maestri lashed out at English referee Wayne Barnes after they were denied a penalty try in the chaotic finale.
France played nine five-metre scrums after Wales were penalised in the 79th minute while leading 18-13 but, despite their utter domination, were never awarded a penalty try.
Damien Chouly eventually bundled over the line after 20 minutes of added time and Camille Lopez converted to give France their third win in the championship.
"He (Barnes) told us we were not dominant enough," Maestri said. "Anglo-Saxon referees always talk about fair play but the reality is that they think we're cheats.
"When you are repeatedly crushed in a five-metre scrum, you concede defeat," he added. "There's a complicity between Anglo Saxons and it is in these moments that you realise it," he said. "It was unbelievable."