Mendy is the third full-back to arrive at Man City in the close season following the arrival of Danilo from Real Madrid and Kyle Walker from Tottenham Hotspur.
City are almost certain to rotate their full backs, with Danilo, who can play on both sides, acting as a cover for Mendy and Walker. Manager Pep Guardiola is also reported to be in the market for another right back to complete a very expensive set.
"I know Mendy, because he's French and he's been playing for my former club Monaco. I think he's a fantastic player," Toure told Sky Sports.
"You will see in the Premier League how powerful he is, how much energy he has. This guy is very exciting to see.
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"I hope he's going to be fine in the Premier League, because it is such a tough league, and we all know you need to adapt for a month or so, or some players go on straight away.
"I hope he can adapt as much as possible because we don't have time."
Mendy, 23, has joined his new team mates in Los Angeles and could make his City debut in a pre-season friendly against Real Madrid later on Wednesday.
(Reporting by Hardik Vyas in Bengaluru; Editing by Peter Rutherford)
