Lyon have insisted Moussa Dembele is not for sale amid reports Chelsea want to buy the striker.
Dembele has hit 25 goals in 51 Ligue 1 appearances since joining Les Gones from Scottish giants Celtic in 2018, though he has only netted one Champions League goal in 12 games for the club.
His form is said to have caught the eye of Chelsea, who are seeking competition for Tammy Abraham after their transfer ban was reduced on appeal.
Reports in France claim Chelsea made an initial offer of €40million (£33.9million) for Dembele, who was linked to Manchester United last July, but Lyon released a statement on Thursday reiterating their determined stance on the 23-year-old striker's future.
"Lyon has taken note of certain information relayed by the media suggesting that Moussa Dembele could interest other clubs during this transfer window," the statement said.
"OL would like to reaffirm its wish, as in the summer of 2019, to keep Moussa Dembele. The club has full confidence in Moussa and counts in particular on him to build a successful team for the seasons to come."
Lyon are 12th in the Ligue 1 table having won only one of their last four league games, but they have a last-16 Champions League tie against Juventus to look forward to next month.
Chelsea are also reportedly interested in Borussia Dortmund's England forward Jadon Sancho, as well as Crystal Palace star Wilfried Zaha, who the Eagles are said to value at £80m.