Real Madrid have made a 160m euros (£137m) bid to sign Paris St-Germain forward Kylian Mbappe.
The French World Cup winner, 22, joined PSG in 2017 in a transfer worth £165.7m and his contract expires in June 2022.
PSG sporting director Leonardo said the club would “not hold Mbappe back” but considered Real Madrid’s bid to be “not sufficient”.
“We consider the offer as being very far from what Kylian is worth today,” he told French radio station RMC Sport.
Mbappe has scored 133 goals in 174 games for PSG and won three Ligue 1 titles and three French Cups.
“If a player wants to leave it must be under our terms. This applies not just to Kylian but to all players,” Leonardo said.
“If he wants to go, we are not going to hold him back, but it is on our terms.”
Real, who lost 300m euros in revenue because of Covid-19, have only signed defender David Alaba on a free transfer from Bayern Munich this summer.
However, this summer Sergio Ramos left on a free to PSG, while another high earner, Raphael Varane, was sold to Manchester United for £34m and Martin Odegaard left for Arsenal for around £30m.
Leonardo said that PSG had made “two big offers” to keep Mbappe at the club and had seen the Frenchman as “the centre of the project” at the club.
“Kylian feels like leaving, this seems clear to me – our goal is to extend and keep him,” Leonardo added.
“With him, we talked a lot, he always told us the same things. He always promised he wouldn’t leave the club free.
“It [Real’s bid] is less than we paid for him. But it’s the way Real Madrid does it that we don’t like.”
It is not known how the fee would be structured.
PSG signed Argentina forward Lionel Messi earlier this month after he left Barcelona.
If Real are successful, it could trigger a number of deals before the transfer deadline at 23:00 BST on Tuesday, 31 August.
It is known Cristiano Ronaldo’s future at Juventus is uncertain and PSG are thought to be interested in the Portuguese, which raises the intriguing possibility of a link-up with Messi, his rival for the world’s best player for well over a decade.
Manchester City are among the clubs to have been offered Ronaldo but are not thought to be interested in a deal.
Last week both Ronaldo and Juventus boss Massimiliano Allegri denied the forward wanted to leave.
Can Real afford it?
Last summer’s transfer window was the first time Real went without a signing since 1980.
Los Blancos have not spent heavily on new signings, since summer 2019 when they spent more than £300m on players headed by Eden Hazard’s arrival from Chelsea.
In addition to this summer’s high profile depatures, last year they sold Sergio Reguilon to Tottenham for £27m and Achraf Hakimi to Inter Milan for £36m.
In their accounts for 2020-21 published in July, Real said: “Current forecasts suggest that recovery to the pre-pandemic situation will not be immediate. Therefore, the Club will continue with the cost containment efforts it has made so far.”
They are also currently refurbishing their Bernabeu stadium with a 575m euro loan.
In January 2021, their gross debt stood at a reported 901m euros.