Lille are close to agreeing a deal with Metz for midfielder Ludovic Obraniak.
The 22-year-old is coach Claude Puel's number one target in the January transfer window.
Lille are understood to have offered an undisclosed transfer fee plus Johan Audel and Daniel Gygax for Obraniak.
While some loose ends still need tying up, Metz director of sports Joel Muller hopes the transfer can be completed by the end of the week.
"There are still a few details to arrange," Muller told the club's official website.
"But we are hoping this file will be closed at the end of the week."