The France striker's move to Monaco was confirmed last night and this morning ASM announced Lopes had made the switch in the opposite direction.
The two deals were performed independently.
Lopes was in Seville last night undergoing a medical and his fee is understood to be for €20-25m.
He said, "I want to thank everyone for the effort, I really want to work for the team.
"I hope to help Sevilla FC. It is a very large club in Spain and Europe. I am so happy to be here."