The centre-back, who was in the sights of Manchester United until they withdrew their interest and was close to joining Lyon, has signed a five-year deal, while Andre Gomes followed the same path on loan.
Mina emerged as a target following his commanding performances at the World Cup but ultimately moved to Everton on deadline day, despite reportedly having agreed personal terms with United.
Zouma spent last season on loan with Stoke too but had to deal with relegation at the end of the season.
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"I know about Everton's players and I look forward to being able to play with my new team". The 23-year-old joined Barcelona only in January of this year from Palmeiras and has seen his stock rise significantly during the intervening eight months.
The coach had been keen on a centre-back to reinforce his squad and many names were mentioned, with several related to Barcelona including Samuel Umtiti, Clement Lenglet and, most recently, Yerry Mina.
'It is important that the club want to fight for something, ' Mina told evertontv.
The French defender played 37 games for the Potters and him returning to the Premier League makes sense for both the club and the player.