Leicester signed Boubakary Soumare from French champions Lille on Friday in a deal worth a reported £17 million (23 million euros).
French midfielder Soumare agreed a five-year contract with the Premier League club.
"I'm really proud to come to the Premier League and a big club like Leicester. It's going to really help me to develop my game and progress as a player, so I feel it is the right step for me," Soumare told Leicester's website.
"Leicester is a very ambitious club. When they spoke to me about their plans and what they wanted from me, I knew straight away I wanted to come.
"I really am so proud and honoured to be here and I will give my all for the team and club to make everyone happy."
Soumare, 22, made his Lille debut in 2017 and made 112 appearances, scoring once. He has appeared for France at every age group from Under-16 to Under-21.
He is Leicester's second close-season signing after Zambia striker Patson Daka joined from RB Salzburg for £23 million this week.