Sane, who had just a year remaining on his Manchester City contract, decided to return to his native Germany for an initial fee worth around £44.7m.
The former Schalke 04 man was linked with the German champion last summer but a serious knee injury during the Community Shield with Liverpool curtailed any potential move before the 2019-2020 season.
Despite refusing to extend his stay at the Etihad Stadium, Sane has revealed that his relationship with Guardiola is still healthy.
The 24-year-old told Bild: "Our relationship is good. There was never a point when one of us was fed up with the other.”
“I'm grateful for everything he's taught me. Pep Guardiola has helped me to reach a very high level.”
"He's very meticulous and wants to help the players progress every day.”
“In terms of his tactics, he's persistent - but that's a positive thing which helped me.”
"We even lived in the same building, so we saw each other regularly."
Sane scored 35 goals and provided 45 assists in 135 games in all competitions for the Premier League outfit.