Mbappe, 23, signed a new lucrative three-year contract at Paris St-Germain instead of moving to the La Liga club.
“His dream was to play at Real Madrid,” Perez told El Chiringuito.
“We wanted to do it last August and they didn’t let him leave, he kept saying he wanted to play at Madrid and 15 days before changed the situation.”
According to Spanish football expert Guillem Balague, Mbappe had agreed a financial package with Real months ago for a potential switch to Spain prior to opting to stay with PSG.
Spain’s La Liga reacted angrily to the news, calling the deal “scandalous” and has since filed a complaint to Uefa about what it believes to be Financial Fair Play breaches by PSG and Manchester City.
“This is not the Mbappe I wanted to bring, he is another one, who must have changed his dream,” Perez was quoted as saying in Marca from the interview with El Chiringuito.
“He changes, he is offered other things, he is pressured and he is already another footballer.
“There is no-one at Real Madrid above the club. He is a great player, he can win more than others, but it is a collective sport and we have values and principles that we cannot change.”
Mbappe has not ruled out moving to Real Madrid in the future, saying it is “never over” when asked about joining the Spanish champions.
Perez added: “The Mbappe who was going to come here is not this one. If it is, I prefer him to stay at PSG. I want the one with the dream.”
Real Madrid won La Liga and the Champions League last season with France striker Karim Benzema scoring 44 goals in 46 games.
He is one of the favourites to win the Ballon d’Or and Perez suggested the 34-year-old’s exploits were behind them not signing striker Erling Haaland, who has joined Manchester City.
“We have the best nine in the world and we weren’t going to bring in Haaland to have him on the bench, right?” said Perez.
“We have no interest now other than to build the new team with the youngsters we have and some reinforcement.”
In the interview, Perez also said the formation of a European Super League “is still alive”.
Real Madrid were one of 12 clubs in a proposed European Super League when plans for the competition were announced last year.
All of the sides, except for Juventus, Real Madrid and Barcelona, pulled out after widespread protests from fans, politicians and governing bodies.