As in Indian Wells and Miami, Sinner had the measure of Zverev, who has not prevailed in their meetings since the round of 16 at the US Open in September 2023.
Extremely aggressive from the start, Sinner blew the German away in the opening set, breaking him three times and wrapping it up in 34 minutes.
In the second set, the German world No.3 put up more resistance, finding his first serve again, but he still had to battle every time to hold.
He finally folded after one hour and 22 minutes on another blistering forehand from Sinner, who has lost only one set in his last 21 matches at Masters 1000 events.
The Italian becomes the first player to reach all three finals of the season's first three Masters 1000 events since Novak Djokovic in 2015. Roger Federer in 2006 and Rafael Nadal in 2011 are the only two other players to achieve the feat.
He will face either world No.1 and defending champion Carlos Alcaraz or local boy Valentin Vacherot, ranked 23 in the world, who meet later on Saturday.
If it is Alcaraz, it will be the first meeting this season between the world's top two players which would decide who will be world No.1 come Monday when the new ATP rankings are released.