Lopes has made only five appearances for English champions City, but the Portuguese midfielder is already regarded as one Adidas F50 Messi
of the club's brightest young talents.
The 18-year-old was especially impressive when he started for City in their League Cup semi-final second leg win at West Ham last season.
City boss Manuel Pellegrini believes Lopes will benefit from a season gaining experience with Lille and the player says he is relishing the chance to play first-team football.
"I feel very happy to have signed because it is a new step in my career and it is a good opportunity for me to develop as a player," Lopes told City's website.
"It is very important for me to play in a professional league for the first Hypervenom Phelon
time. I think playing in the French League will be very beneficial because it is a league that is getting bigger, better and stronger every year."
Lille finished third in Ligue 1 to qualify for the preliminary stages of the Champions League.
And Lopes added: "It would be very exciting to be able to play Champions League football.
"It would be such a good experience for me to play in that competition, which everyone recognises as the best in European football."