Earlier this year just over 50% of French voters said Marine Le Pen ’s National Rally party posed a threat to democracy. On Sunday she will appeal to the other half in an attempt to pull off an election result that could reverberate across Europe.

Her party is set to emerge from the vote with the largest number of seats in parliament, even if an outright majority looks out of reach. Either outcome would be an unprecedented development in France's postwar history, a crushing blow for President Emmanuel Macron, and lead to years of turmoil in the European Union's second-largest economy.