James departed French football this summer after a stellar World Cup with Colombia, bagging Monaco an estimated £63 million from Real Madrid.
Girard, who guided Lille to third in Ligue 1 last season, believes Brazilian-born Portuguese Lopes shares plenty of characteristics with James and tipped the 18-year-old to make a major impact.
"Our gazes fell on Lopes," he told RMC Sport. "City needed to loan out this young Portuguese lad.
"He comes having participated in this year's Under-19 European Championship, where Portugal were beaten by Germany in the final.
"He has a great left-foot and is a good passer. If I was to compare him in style to anyone, I would say that James Rodriguez and him share plenty of similarities.
"What he brings us is bundles of technique. He is young and ambitious. After a discussion with their reserves coach Patrick Vieira, Man City decided that Lille would be an ideal place for him to grow further as a player."
Lopes, who was named City's 2012-13 academy player of the year, has made five competitive appearances for the Premier League champions' senior team over two seasons, all of which came in domestic cup games.