Salomon Kalou has completed his move to Lille, joining the 2011 French champions on a free transfer.
The former Chelsea winger has signed a four-year deal, the club have announced on their official website.
"Lille confirm the signing of Salomon Kalou, who passed a medical this morning after arriving at the club last night," a statement said.
"Agreed in principle at the end of June, the European champions have signed a four-year contract until June 2016."
Kalou revealed that the club's ambition with a project he believes in were the reasons he joined.
He said: "Lille's project, notably with the impending new stadium, is ambitious and really pleased me. Given what I already knew about the club, there is nothing more you could ask from Europe's biggest clubs.
"I am excited about coming here and look forward to meeting the warmest of fans."
Kalou is replacing Eden Hazard, who went in the other direction last month.
