$230m price tag bandied about for Real superstar

United's Jose Mourinho could be interested. Photo / Getty Images

Cristiano Ronaldo's advisers are telling clubs that he wants to leave Real Madrid for a "fresh challenge", with a fee of 150 million ($230m) being mooted, and not because of the accusations of tax fraud he is facing in Spain.

Although that claim will be met with understandable scepticism, not least because of the briefings from Ronaldo's camp this week, clubs are nevertheless being encouraged to believe he is serious in his desire to quit and would welcome offers.

Having won the Champions League three times in four seasons and winning La Liga again, it is argued by sources close to Ronaldo that, aged 32, he wants to move on for football reasons and has done all he can in Madrid and in Spain.

There is, however, one big problem with this argument and that is the fact that Ronaldo signed a new five-year deal with Real only last November. The buy-out clause is 1 billion, which is obviously unachievable, but a world-record bid of 150m may be forthcoming.

That is the figure which is circulating in football and might tempt, in particular, Paris Saint-Germain (PSG) to make such an offer, while Jose Mourinho's Manchester United remain interested and could also go that high.

There could be a new suitor in Inter Milan, who are spending big under their Chinese ownership. If he leaves Madrid, Ronaldo wants to stay in Europe which would rule out a move to the Chinese Super League.

PSG are rebuilding this summer and have earmarked a budget of 220m to sign up to six new players under their new and highly-rated sporting director Antero Henrique, who has been recruited from Porto.

PSG do not want to blow all their money on Ronaldo, but will generate funds on top of their budget through sales - seven players are up for sale - so may have even more to spend.

They have long courted Ronaldo and have an open dialogue with his agent Jorge Mendes, the representative for PSG player Angel Di Maria, who may be one of those to leave, and also James Rodriguez and Pepe, who are leaving Real and have both been offered to PSG. Henrique also has a strong relationship already with Mendes and knows his fellow Portuguese, Ronaldo.

PSG have previously pointed out to Ronaldo's representatives that Paris has the largest Portuguese community outside of Portugal in Europe - there are 1.2 million in the French capital - and he would be an instant hero at the club where the challenge would be to regain the French league and, more than that, win the Champions League for the first time in their history. United also remain a possibility and there is strong admiration for Ronaldo and the way he has reinvented himself as a central striker in the past couple of years. The fact that he is 32 is not a concern given the way he looks after himself and has not suffered any serious injuries in his career. There is, therefore, genuine belief that Ronaldo could remain at the top for another four years.

However, United are wary given Ronaldo was expected to return to them in 2013, almost as Sir Alex Ferguson's parting gift to his successor David Moyes, only to change his mind and sign a new deal at Real.