The two-day World Summit of Regions for Climate showcased efforts to mobilise business sectors ahead of next year's UN climate conference in Paris.
It will bring together world leaders to discuss a deal on cutting carbon emissions.
The conference proposed that states, regions and cities sign on for common concrete actions.
The question of a worldwide climate deal has been up in the air since fell apart at the 2009 UN conference in Copenhagen.
Speaking at the Paris event, UN special envoy for climate change Mary Robinson said a fair agreement would put a bigger burden on industrialised countries.
“If we are to reach zero carbon in 2050, the parts of the world that have benefited from fossil-fuel-led economy must move more quickly, must do more to move to renewables,” she said.
Poorer countries in Africa and south Asian countries suffer the effects of climate change but do not have the technology that can reduce their reliance on coal, she argued.
“We don’t see a solidarity yet of the richer countries,” Robinson said. “They have to take the primary responsibility.”
Schwarzenegger met French president François Hollande on Friday.
On Saturday Foreign Affairs Minister Laurent Fabius commented that the former action film hero has gone from “Terminator” to “Visionator”.