Rudi Garcia admits it is imperative Lille retain the services of their key men if they are progress.
The club have impressed greatly this season, with the Ligue 1 title edging into view with each passing week.
Few tipped Lille for the Ligue 1 crown this season, but they have led the way for much of the campaign.
That success has been down to a combination of good management and players fulfilling their potential.
Unfortunately for Lille, a number of those to have shone brightly this season are now attracting interest from rival teams.
Garcia appreciates that there will always be attention placed on good players, but has called on the club to ensure that mass sales are not allowed to undermine all the hard work he has put in.
He told L'Equipe: "Our new stadium is coming in 2012 and we are playing really good football. Lille has probably the best project going on in France.
"We now need the financial means to keep our best players.
"It is going well for the likes of Mickael Landreau, Rio Mavuba and Mathieu Debuchy, it is important they stay.
"The biggest danger is losing too many players. We already know that Adil Rami is off to Valencia. Even one more departure could be very harmful."
Discussing his own future, with a contract extension having been touted, Garcia added: "My extension? There is no problem there. I will be Lille coach next season.
"I am happy to be part of this project and I want to go as far as possible. But I also want to have a team that looks like the one I have at the moment."