The 46-year-old won 14 trophies during his four-year spell in charge of Barca as the Catalans became the team to beat with their famous 'tiki-taka' style.
He stepped down as Barca boss in 2012, only to return to coaching at Bayern after a one-year sabbatical, guiding the Bavarians to three consecutive Bundesliga titles during his time at the Allianz Arena.
However, Tuchel was not overly impressed with the Bavarians' style of play under the current Manchester City boss.
"The way Bayern played under Pep was different to how Barcelona played under him. For me, Bayern were not as fluent, rhythmic, fresh and completely different as Barcelona were under Pep," Tuchel said during a podium discussion hosted by Sport1.
"He came very close in his first few months. I remember a game against Manchester City and I was thinking, 'this is unbelievable, we have reached this point again'. Nobody could touch the ball and you could almost play music to their rhythm.
"But the ongoing development and attempts to minimise risks was too rational for me. They kept on winning and winning after that great start and still got 90 points or so, but it was no longer as beautiful to see.
"It was all planned through and through, they suffocated opponents. Things became more static. It was even more impossible to counter-attack against them in their 4-1-4-1. They were very clinical. They would always score.
"They were incredibly consistent, but they were no longer entertaining romantics like at Barcelona or during his first six months at Bayern.
"I remember a game where Bayern were trailing and he played two strikers up front, I think [Claudio] Pizarro and [Mario] Mandzukic. At Barcelona, he would have rather lost as a protest than play with two big strikers."