Trades took place between the teams. French champions will be joined by Sebastien Squillaci, and Sylvain Monsoreau will play for the "Monaco" team.
S.Squillaci signed a four-year contract with the "Lyon" club after successfully passing a medical examination.
The Frenchman is pleased that he will be able to play in the French champions club: "When a club of this level shows interest in me, from my side there are no doubts about accepting the offer," S.Squillaci officially stated on the club's website.
"Competition in defense? It's part of the game that exists in all clubs. It all depends on me - I will try very hard to secure a place in the main team," added the player.
Last season, the "Lyon" team became the French champions for the fifth time in a row and performed well in the Champions League, while "Monaco" only finished 10th.