Lyon unveiled new signing Nicolas N'Koulou on Wednesday amid reports a fee has been agreed to sell fellow defender Samuel Umtiti to Barcelona.
The Liga champions have been heavily linked with centre-back Umtiti, who is currently part of France's squad at Euro 2016, as they look to bring in defensive reinforcements during the transfer window.
According to French media, Barcelona have now approved a EUR30 million deal for the 22-year-old, although he has not yet discussed personal terms.
At a press conference to introduce N'Koulou, Lyon president Jean-Michel Aulas revealed he had promised not to stand in the way of Umtiti joining the "club of his heart".
N'Koulou is a ready-made replacement after arriving from Ligue 1 rivals Marseille on a free transfer.
The Cameroon international has signed a four-year contract that will keep him at Parc Olympique Lyonnais until 2020.
"I come here with a lot of ambition," the 26-year-old told Lyon's official Twitter account.
"I spent five wonderful years at Marseille, I was at the end of contract and need to turn the page.
"I am here because Lyon is a club that will help me continue to grow."