French sports newspaper L'Equipe had reported "traces of corticosteroids" - which are used to help reduce inflammation - were found in the urine samples given by the Racing players to the French anti-doping agency.

Carter, Rokocoko and Imhoff maintained their innocence throughout and were defended by their club, whose position has been vindicated by the FFR's verdict.

A statement released by Racing read: "The medical commission of the FFR has duly dispelled any doubts over-shadowing the medical practices of the club.

"As we have always stated, neither the players nor their doctor committed the slightest violation of the rules or the slightest ethical breach."

When the report first appeared on October 7, the management company representing Carter and Rokocoko said it had been ''aware of the issue for a few weeks''.

The Essentially Group's Simon Porter told the New Zealand Herald: ''Our understanding and the assurances we've had are that all the documents around TUEs (therapeutic use exemptions) were in place.''

Carter was receiving medication for a calf injury, Porter said, while Rokocoko was recovering from a knee problem.

Racing's initial statement appeared to indicate TUEs were not in place, with the club confident they were not required.

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World Cup winner Carter used his Instagram account to express his relief at the judgement.

"I just received the ruling from the FFR. No surprises that the FFR's ruling was that I'd done nothing wrong," he said.

"I hold my integrity and the game of rugby's integrity in the highest regard.

"I love this game and owe so much to rugby that I would never do anything intentionally to bring it into disrepute.

"I am glad that we can now put all this behind us so I can now concentrate on playing rugby!"