St Etienne coach Claude Puel is angry they face losing William Saliba to Arsenal at the end of the season.
The defender was signed by the Gunners at the end of last season and loaned back to ASSE for this term.
And new coach Puel says: "It's hard to accept that we are selling our best player, a young boy, to fill the club's coffers.
"The moment you sell your talents to keep the budget tight, you have to cover their departure with players for the short term."
He added: "I'd rather see us get a young player and help them grow than buy an established player."