The deal could be worth AED251 million.
Sane, 24, says Bayern Munich is a "great club " after he signed a five-year contract at the Bundesliga side.
The Germany winger is leaving Manchester City who he joined from Schalke in 2016 for AED169 million.
The football star has won two Premier League titles, the FA Cup and two League Cups.
He says his priority is to win as many trophies as possible with Bayern, and he's targeting the Champions League.