Claudio Ranieri has splashed out £13million to sign the highly-rated midfielder – beating the Foxes previous record of £9million for Croatian striker Andrej Kramaric.
Mendy’s arrival will be viewed by many as Leicester doing their business to clear the way for star midfielder N’Golo Kante to leave the club.
The French ace, currently starring for his country at Euro 2016, is wanted by a string of Europe’s top clubs, including Chelsea, Arsenal, Real Madrid, Juventus and PSG.
Kante – who cost Leicester £5.6million from Caen last summer – is seen as one of the biggest bargains in Europe at the moment because he has a £20million buy-out clause which can be triggered at any moment.
However sources close to Ranieri insist the Italian wants Mendy to pair Kante, not replace the driving force in his midfield.
Speculation over Kante’s future has increased since the 25-year-old declined to sign a new contract offer which would have seen him pocket £100,000 a week.
He is believed to favour a move to Chelsea where he is keen to play for another Italian boss, Antonio Conte.
But Ranieri is equally determined to strengthen his Foxes squad as he looks to defend Leicester’s title and handle the additional demands of Champions’ League football next season.
Mendy’s arrival will certainly help last season’s surprise package to maintain their stunning progress.
The 24-year-old Frenchman completed his medical and tied up the final details of his record £13million move from Nice yesterday to complete months of painstaking scouting by Leicester’s highly-regarded scouting team.
The midfielder was regarded as one of the most creative playmakers in French football last season and is seen as the perfect provider for speedy striker Jamie Vardy with his ability to split defences with raking crossfield passes