It was the cheapest of cheap shots and the fact that Sam Cane went unpunished even after a disciplinary committee reviewed his reckless tackle on Robbie Henshaw made a mockery of the warning that World Rugby had issued prior to the November Tests.
Henshaw was stretchered off after just 10 minutes of Ireland's defeat to New Zealand and subsequently spent the next three weeks out with concussion, while Cane was free to play.
There has been a plethora of contentious incidents over the last few months, which has meant that World Rugby have again had to review the laws, and the new 'zero tolerance' edicts they introduced have hardly come as a surprise.
Had they been in place that night in Dublin and properly governed by referee Jaco Peyper, there is no doubt that Cane would have walked.
That was then and this is now, and Henshaw for one is relieved that the governing body have taken such a hard stance on any potential high tackles.
It means that players must rethink the way they are entering collisions and Henshaw, who tends to target the chest area of opponents, accepts that the responsibility is on himself to ensure that the hits he puts in are not deemed dangerous.
"I think it's good that World Rugby are clamping down on high tackles because it is an issue where the player on the other end of the tackle can suffer and miss vital games," he said.
"It's good that World Rugby are taking it into their own control. It has to be implemented to tackle below the shoulders because head hits are dangerous.
"I'm in favour of it. It's all down to the ref at the end of the day what the decision is. But we're in control of our actions and we can avoid that by tackling lower."
While his coach Leo Cullen insisted last week that the laws hadn't changed appreciably, Henshaw believes that there has to be a shift in the mindset of players, and that begins in training.
"You have to practise your body height when you're dipping late from high to low and showing a different picture. A lot of my tackles would be quite chest high so I'll need to work on it a bit myself," he said.
There were several questionable decisions last weekend as World Rugby's new laws came into force for the first time; Ulster in particular felt that they were on the receiving end of a harsh call when Sean Reidy was shown a yellow card and a penalty try was also awarded in the same incident.
By the letter of the law, referee Marius Mitrea had little option, even if Reidy's tackle wasn't all that dangerous, and Henshaw said he had sympathy for his Ireland team-mate.
"I've seen those let off before. I think it's a statement from World Rugby and the referees department that they really want to clamp down around the neck and head areas," he said.
"Maybe it was a bit harsh on Sean Reidy. Maybe they might ease off on that a little bit because maybe it was only a penalty.
"Over the weekend, you saw a couple of yellow cards given out quite easily for tackles that wouldn't have even been penalties in the past.
"I think every player has to address himself and tackle a little bit lower because you can't risk 10 minutes in the bin or else your team will suffer."
In Paris on Saturday, Matthew Carley showed plenty of common sense when he twice penalised Racing for dangerous tackles. Neither warranted anything more than a penalty and the referee kept his cards in his pocket. Rassie Erasmus had no complaints.
"I thought he was spot on with it," Munster's director of rugby said. "We had two high tackles early on us, which I think, having watched the Friday game and the Saturday game before us, those referees would have given yellow cards and even penalty tries somewhere.
"The referee really handled it well. It was just high tackles, it wasn't guys who on purpose wanted to smash someone in the face. I will never criticise the reason why they're doing it, because it's spot on: you can't tackle guys around the neck.
"If the coaches and players stay honest about it and the referees understand what they're trying to do, I think it will work."
The likelihood is that we will see more debatable decisions in Europe this weekend but once the players and referees have time to adjust to the new laws, the feeling across the board is that it will make rugby a safer sport, and that can only be a good thing.