However, his club Manchester City are playing hard ball and holding out for a mega fee.
Matthus believes Bayern are prepared to pay that sum, even if it goes to €100 million.
He said to reporters: "I don't think this transfer will fail because of a few million euros.
"If the player gives the Bayern bosses the signal that he wants to join them, I'm sure that the club will be ready to pay an amount in the three-digit million range.
"Bayern will have to strengthen offensively if they want to be internationally successful. And for this purpose, this transfer would be a great signal. And a little bit more quality simply costs a few million more."