Newly-appointed boss Claude Puel has claimed that Saint-Etienne should not have considered selling William Saliba to Arsenal.
While the highly-regarded prospect has remained at the Ligue 1 side for this season, Saliba has already agreed to join the Gunners in the summer.
However, Puel has criticised the decision to cash in on the 18-year-old, suggesting that the teenager should have been given the opportunity to develop at Stade Geoffroy-Guichard.
Puel told L'Equipe: "It's done, adopted and I've got nothing to say because it helped perform. Saint-Etienne have held their rank these past few years. Finishing fourth is a great result. Work was done in the short term.
"Is this model viable? I don't think it can make the club a success. Rather than buying a ready-made player, I'd rather we buy him to develop him and help him grow. It's hard to accept that we sell our best player, a young kid, to help fill the coffers.
"When you have to sell your gems to round up the budget and then do short term deals to fill in the gaps, you're being reactionary."
Puel is unbeaten in his opening four matches at Saint-Etienne after being brought to the club on October 4.