"Arctic Oil? Shell no!" read the banner dropped from the roof of the stand opposite the VIP seats as teams readied their cars on the starting grid.
The race, with Lewis Hamilton on pole for Mercedes, started on schedule.
Images of the action, with police using a platform to try and reach the activists, were not shown on the television feed watched by millions around the world although they were widely shared on social media.
Greenpeace said in a statement sent to Formula One media that two paragliders had also flown over the circuit trailing banners. Shell are also long-standing partners of the Ferrari team.
Shell cancelled its 2013 Arctic offshore drill season after numerous troubles there last year but plans to send ships to study sites around oil prospects in the Chukchi and Beaufort seas, according to permit applications.
The U.S. Geological Survey estimates the Arctic may hold 13 percent of the world's undiscovered oil and 30 percent of its gas.
"This Grand Prix is Shell's biggest day of the year. They've spent millions of euros plastering their logo everywhere and entertaining scores of VIP guests, but the one thing they don't want to talk about is their plan for Arctic oil drilling," said activist Tony Martin in the Greenpeace statement.
(Reporting by Alan Baldwin, editing by Pritha Sarkar)
