Swansea City striker Eder will spend the remainder of the 2015-16 season on loan at Lille after failing to score in 15 appearances.
The 28-year-old only arrived at the Liberty Stadium in June, but has struggled to settle into life in the Premier League.
With only four starts in all competitions and the arrival of Alberto Paloschi, Eder has been allowed to leave the strugglers and get more first-team football in Ligue 1.
"I am very happy to be here," he told Lille's official website. "I was extremely well received.
"I also liked the first contact I had with the coach and the entire technical staff. I am quite impressed with the standard of the facilities that are of a really high quality.
"I now look forward to getting to know my new team-mates, train and play in this shirt."
Eder arrives at Lille with the club 15th in Ligue 1, six points clear of the bottom two after 23 matches.