Financial details of the deal were not disclosed but local media reported that Monaco paid Sevilla about €40 million to activate 29-year-old France international Ben Yedder's release clause.
Ben Yedder joined Sevilla in July 2016 and scored 70 goals in three season at the La Liga club.
"I am very happy to be involved with AS Monaco," he told Monaco's website.
"I chose Monaco because I believe in this project and I am determined to do everything possible to go after our common ambitions."
Lopes, who can play on either wing, came through the ranks at Benfica and made his professional debut for Premier League champions Manchester City at the age of 17 during the 2011-12 season. He has signed a five-year contract at Sevilla.
Monaco, who finished 17th in the 20-team Ligue 1 last season, began their current campaign with a 3-0 home defeat by Olympique Lyonnais on Friday.