While the Europe Ecology-The Greens party will be toasting their unprecedented triumph, it came amid a record abstention rate of 59% across the country.
The first round of the elections had taken place in March just before the country locked down over COVID-19.
The government had been heavily criticised for maintaining the vote.
More than three months on, voters were greeted by officials wearing plastic visors to prevent the spread of coronavirus, with the country still in the grips of an epidemic. Some workers were protected by plexiglass.
Voters wore masks, brought their own pens, and waited in socially distanced queues to get inside schools and town halls to vote.