The far-right National Front party has topped the poll in France's first elections since the Paris attacks.
Exit polls suggest they gained up to 30 per cent of votes in the first round of regional elections.
The party, led by Marine Le Pen, promotes anti-immigration policies and has been accused of Islamophobia.
The National Front is ahead in 6 out of 13 regional constituencies.
A run-off poll takes place next Sunday, when the party is expected to take control in at least 1 region for the first time.