Ronaldo isn't the first major football star to be accused of defrauding the authorities, as Lionel Messi has been accused of similar crimes as early as 2016.
Mourinho left the club in 2013 to return to Chelsea. And finally, they accuse him of "voluntarily" refusing to include 28.4 million euros in income linked to the sale of his image rights for the 2015 to 2020 period to a Spanish company.
According to media reports Ronaldo is unsettled at Real Madrid because he believes the European champions did not back him as fully as he had hoped in his dispute with the taxman.
President Perez, when asked about the Portuguese, noted that the 32-year-old was "bigger than all of us" and insisted he would remain at the Berbabeu.
He denies the accusations and is threatening to leave Spain.
Speaking about Ronaldo's reported desire to leave the club, Perez added: 'Not I, nor anyone at Madrid, is contemplating that Cristiano could leave the club'.
"It has affected me how the media treated Cristiano; the presumption of innocence was not respected. I don't know if Zidane has called him as well, I am not going to do it because I want him to rest during his holiday".
Mourinho, 54, is accused of two counts of tax fraud - €1.6m in 2011 and €1.7m in 2012.
Ronaldo joined Real from Manchester United in 2009 for a then world record fee of 96 million euros and is their all-time top scorer with 404 goals in 394 games.