On paper, it looked to be a great move as Magpies chief scout Graham Carr had picked up some gems from the French market, including Hatem Ben Arfa, Yohan Cabaye and Moussa Sissoko.
But things quickly turned sour, and with the Toon now looking at a move for Rayan Cherki, Thauvin's signing could serve as a warning to the club's transfer team.
Of course, Newcastle are very different these days and are yet to make a major mistake in the transfer market, so if they do recruit Cherki, it's because they believe in him.
Still, it's intriguing to look back at Thauvin's move to Tyneside and assess what went wrong.
Like Cherki, the winger was one of the brightest talents in France when the Magpies plucked him from Marseille in 2015 for just £13million.
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The 22-year-old made his debut in a 0-0 draw with Manchester United at Old Trafford and looked lively in the Toon's following game against Arsenal.
The French international then showed the St James' Park faithful what he was capable of in a 4-1 win over Northampton Town in the League Cup.
Thauvin scored his only Newcastle goal with an acrobatic volley before setting up the other three.
Although the opposition weren't the strongest, Thauvin still looked to have the raw talent that would excite people.
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But that was as good as it got, as the following Premier League match, he turned up wearing a full tuxedo.
Newcastle lost 2-1 to Watford and Magpies legend Alan Shearer ripped into the young Frenchman.
Shearer speaking on Match of the Day said: "He turns up in a tux. This is a serious business we're in here, it was funny on the first day of the season, it's not funny any more.
"Look at [Allan] Nyom run past Thauvin. You might be able to do that in the French league, you can't do that in the Premier League."
After this, he was benched and only started one further league game.
Newcastle were embroiled in relegation trouble and Thauvin was struggling.
In January 2016, he rejoined Marseille on loan and never played for the Magpies again, although he officially left permanently in the summer of 2017.
While in Newcastle, the forward thought his career was over.
Speaking about the move to Onze Mondial, he said: "Over there, I thought my career was f*****.
"I came home in the evening and told my girlfriend that 'this was it - it was over'.
"I wasn't playing at Newcastle. I ended up at this club lost, no one talked to me. My phone never rang."
Thauvin was clearly lonely in Newcastle and didn't get much support from the club, plus he later admitted to uefa.com that the move to Tyneside wasn't what he needed.
"It was too early for me.
"It's a transfer that happened quickly. Normally, you take your time, you think about it, but for me, it all happened too quickly after [Marseille boss] Marcelo Bielsa's departure."
Of course, you could argue that Thauvin should have stuck it out, but he was a young man hundreds of miles from home.
Had Thauvin's move to Newcastle happened at a different time, things could have turned out very differently.
Instead, he returned to France and produced three incredible seasons for Marseille.
The winger scored a staggering 59 goals in all competitions and earned himself a spot in the 2018 France World Cup squad.
He only played in one match across the tournament and hasn't played for Les Bleus since 2019, but he has a World Cup winner's medal, and no one can take that away.
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Thauvin was considered one of France's greatest talents, and though he never lived up to that tag, many Toon fans must wonder what might have been.
Instead, he will be remembered as one of many missed opportunities during Ashley's time at St James' Park.