World Cup - Warburton gets three-week ban
The 23-year-old was dismissed by referee Alain Rolland for the dangerous tackle on winger Vincent Clerc inside the first quarter of Saturday's match at Eden Park, which the French edged 9-8 despite a brave performance from the Welsh.
Warburton, who has 48 hours to appeal, was handed the punishment after a disciplinary hearing and will miss Friday's third and fourth place playoff against the losers of the second semi-final between hosts New Zealand and Australia.
"The independent judicial officer ... determined the ordering off to be appropriate in law and the action in line with IRB directives," read a statement issued by tournament organisers.
Warburton admitted the offence, the statement added, and had avoided a more lengthy ban because of mitigating circumstances, including his "outstanding character, disciplinary record and remorse".
Wales coach Warren Gatland and many of his team had condemned the dismissal as excessive for a tackle Warburton maintained was not malicious, suggesting that a yellow card and 10 minutes in the sin-bin would have been more appropriate.
Spear or tip tackling, where a player lifts an opponent into the air and returns them to the ground head first, is outlawed because of the potential for head injuries.
The governing International Rugby Board issued a statement on Sunday reiterating their "zero tolerance" on dangerous tackles.
Wales defence coach Shaun Edwards told reporters on Sunday he felt consideration should be given to intent in such matters.
"It was not deliberate what Sam did," he said. "I have seen it deliberate where you put your hand underneath, lift him and spin him, and I have had it done to myself and it is horrible.
"You know it is deliberate when you see someone put the hand underneath the crotch and spin him around and drop him to the floor and basically follow on yourself."
Edwards said Warburton's size and strength had caused the tackle to look worse than it was.
"With Sam, it was a dominant hit as you expect. He was much more powerful than the guy he tackled and he ended up in a position that got him sent off. I am not sure if the rest of the officials thought the same way," said Edwards.
"What happened with Sam, in speaking to him, was that he felt the guy was very light in his hands."
The playoff between the losers of the two semi-finals, which will take place on Friday, is usually a match which has little appeal for fans and players alike.
Having exceeded expectations with their run to the semi-finals, however, many of the Wales players said they would be taking the game very seriously.
"Before the tournament nobody gave us a shot of coming third in the World Cup, so we'll definitely be up for it," centre Jonathan Davies said after the match.
Overwhelmingly, though, the sentiment in the Welsh camp was one of having had their opportunity to reach a first final taken away despite playing some of the best rugby at the tournament.
"I am obviously empty really," Edwards added. "We are not playing in the premier event in world rugby and I think in the opinion of the rugby world we could or should have been there.
"I think there is a sense of disappointment that a team that has acquitted itself so well and wants to play rugby is not in the premier event of the sport."