The German driver won from pole position for his fourth career success in the all-electric series while compatriot Pascal Wehrlein finished sixth for Porsche and retook the championship lead.
Stellantis marque Maserati made their debut in the championship this season with what was previously the Monaco-based Venturi team and is now Maserati MSG Racing.
The Italian brand's last previous win in a single-seater world championship was with the late Argentine great and five-times F1 world champion Juan Manuel Fangio in the 1957 German Grand Prix.
Jake Dennis (27) finished second for Avalanche Andretti, with the Briton moving to a point behind Wehrlein, and New Zealander Mitch Evans (28) was third for Jaguar.
Previous leader Nick Cassidy (28) of New Zealand failed to score for Envision Racing and is five points behind Dennis.
Porsche lead the team standings with 212 points to Envision Racing's 190 and Jaguar's 171.
