Mendy worked with Ranieri during Monaco's successful promotion to Ligue 1 in 2013.
Nampalys Mendy has told French newspaper L'Equipe that the chance to work under Claudio Ranieri was a key factor in his decision to join Premier League champions Leicester City this summer, adding that his new boss will help him improve as a player.
Mendy played under the Italian at former side AS Monaco, helping achieve promotion to Ligue 1 in the 2012-13 season, and they are now set to work together again.
The 24-year-old has signed a four-year deal at the King Power Stadium after completing a £13 million move from Nice.
And he admits that the chance to work under his old boss again was a key factor in helping him decide to make the move to the Foxes, who began preparations for their Premier League title defence by returning to pre-season training on Monday.
Speaking about seeing Ranieri again, Mendy told L'Equipe: "Our initial reunion went well. I was able to have my first discussion with him and he immediately put me at ease. He was happy to see me again and vice versa. He played a big part in me coming to Leicester.
"He knows me and he knows how to improve me. He knew how to do that perfectly at Monaco. He is the same person, loyal to himself and always joyful. Even if he is pernickety and demanding when it comes to work."
Mendy has so far spent his entire career in France and admits that English football will represent a significant step up.
But he has been impressed by what he has seen since arriving at his new club and insists he will have little trouble in adapting.
He added: "My first impressions are very good. Everyone came to me to aid me in settling in. It allows me to get my bearings quicker even if I do not speak the language well and that I am, for now, the only Frenchman here. I cannot wait for the entire squad to return and to get to my English lessons."