The Uruguayan forward has been linked with a move to Real Madrid following his exploits in Russia where he scored three goals in four matches.
But Tuchel is convinced the striker will still be in Paris when the transfer window closes at the end of August.
Watch what he said below:
The former Arsenal skipper left his post as head coach of Major League soccer side New York City FC to replace Lucien Favre at the Allianz Riviera.
The 41-year-old Frenchman had been linked with replacing Arsene Wenger at Arsenal following his departure but he now returns to his homeland to take charge of a Nice side that finished eighth last season.
After joining the Gunners in 1996, Vieira went on to win three Premier League titles, including captaining the club during their unbeaten ‘Invincibles’ campaign of 2003/04.
He would then win four successive Serie A titles at Inter Milan before lifting a fourth FA Cup of his career having returned to England with Manchester City.
Add to that a 1998 World Cup winners’ medal and success at Euro 2000 and Vieira’s distinguished career is one that many will remember.
But the man himself is keen to put that to one side as he looks to build on the work he did as the Manchester City academy boss and during his two and a half year stint with NYCFC.
“My career as a player no longer counts, it’s part of the past,” he told reporters at his unveiling on Monday afternoon.
“The important thing for me is to have a clear idea of what I want from players, a specific game scheme for them to express themselves, because the talent is there.
“I’m happy. This is what I was looking for: I will work in good conditions with passionate people, who will support me in the good and bad times. I am very happy to be here. There is everything you need here to succeed.”
Announcing Vieira’s departure on their official website, New York City were quick to thank their former coach for his endeavours.
“New York City FC today announced that Head Coach Patrick Vieira is leaving the Club to join OGC Nice, effective immediately,” the club’s statement read.
“Vieira departs after two and a half years at the helm having led the team to two consecutive play-off appearances and with a current second place standing in the Eastern Conference.”
David Villa, NYCFC’s most high-profile player and another man to have lifted both a World Cup and a European Championship title, tweeted his own message to Vieira.
“Thank you for everything you’ve done for the club, @OfficialVieira. You are not only a great coach but also a fantastic person. It was an honor to play for you and your staff (Christian Lattanzio, Kristian Wilson & Matthew Cook). Wishing you all the best in your future endeavors (sic),” he wrote.
There are also some big names waiting for Vieira in southern France with former Manchester City team-mate Mario Balottelli the stand-out talent.
The controversial Italy international hit 26 goals for Nice last season and has been linked with a summer move to rivals Marseille.
But Vieira revealed he has spoken to the 27-year-old and expects the forward to be present for pre-season training.
“I called Mario Balotelli to wish him a happy holiday,” he added.
“Also to tell him that we would see each other on July 2nd at the resumption of training. But I take one thing at a time.”
Nabil Fekir hailed the perfect ending after Lyon clinched qualification for the Champions League in dramatic fashion.
OL needed to beat Nice to secure third place in Ligue 1 and they did so thanks to a hat-trick from Memphis Depay in a 3-2 victory.
It looks set to be Fekir’s last match for Lyon, with the playmaker heavily linked with a summer move to Liverpool, and if that is the case then he will leave on a high.
He told Canal+: “I spent an exceptional season here, with an exceptional crowd, exceptional players, with an exceptional staff. And tonight we finished in style.”
Lyon should have wrapped up third place last weekend only for Strasbourg to score two late goals, and the nerves were jangling when Alassane Plea gave Nice an early lead.
But Lyon responded brilliantly at the start of the second half and Depay looked to have settled matters with his third four minutes from time only for Plea to score again.
Lyon boss Bruno Genesio appears to have resigned himself to losing Fekir and paid tribute to the France international.
— Nabil Fekir (@NabilFekir) May 19, 2018
He said: “We are still a young team. There will be changes in the off-season. I savour that after this qualification. We did not panic after the first goal. I take my hat off to Nabil Fekir for his return to the top level. Thanks to him.”
Genesio added: “I was calm until the second Nice goal. We qualify and that’s the most important thing.
“The players gave everything. It’s good to see the players together at the end. I thank them. They showed incredible spirit. I have always been supported and we have the result tonight.”
Defeat was a bitter pill for Nice, who started the day in sixth place but were overtaken by Bordeaux and St Etienne and missed out on qualifying for the Europa League.
It was also confirmed post-match that manager Lucien Favre, who has been tipped to take over at Borussia Dortmund, will leave the club.
Defender Dante said on Canal+: “We had prepared well for this final. We had to win. It still remains a good match. I think that if we had played like that all season, we would have already achieved our goals for a while.
“The club progresses, we could do more this season but football does not always happen as we want. We gave everything but we also learned a lot of lessons for the years to come.”