Paris St Germain have turned down Real Madrid's bid for Kylian Mbappe and branded their approach for the player "illegal".
PSG sporting director Leonardo admits the France forward, who has only one year left on his contract, is angling to leave the club.
However, Leonardo insists Mbappe will only be allowed to move to Madrid if their valuation is met.
"Kylian Mbappe wants to leave, it seems clear to me. If Real Madrid makes an offer, it seems clear to me. I am giving a position, which I think is clear to everyone," Leonardo told French radio station RMC Sport.
"We cannot, in the last week of the (window), change our plans. If he wants to leave, we are not going to hold him back, but it is on our terms."
Mbappe moved to Paris from Monaco in 2017 in a transfer worth £165.7million. Real's bid is understood to be around £30million less than that figure.
The 22-year-old has scored 133 goals in 174 matches for PSG and won three Ligue 1 titles and three French Cups.
But PSG's attempts to extend his contract have so far failed, and they believe Real's ploy is to sign him for nothing next summer.
"Kylian was given two important offers. One at the level of the top players in the squad two months ago and one above these players very recently," added Leonardo.
"We want to prove to him that he is an important player, at the centre of the team, but not above the team.
"Compared to Real's position, it looks like a strategy to get a 'no' from us, to show that they have to try everything and wait a year to have (him for) free.
"It's been two years since Real behaved like this, it's incorrect, illegal even because they contacted the player. This is unacceptable to us.
"This is the very proof of the strategy; an offer arrives one year from the end of his contract and seven days from the end of the (transfer window). They want a refusal to show Kylian that they have tried everything and start negotiating for next year.
"We said no verbally. But no one is being held back. If someone wants to leave and our conditions are met, we will see.
"But we created a dream with our players this summer and we won't let anyone destroy it. The offer is considered to be very far from what Kylian represents today."