Marine Le Pen has called for France to take back powers from the EU, saying she wants to “give back to the French the keys of the house”.
The far-right leader, one of 11 candidates standing in Sunday’s presidential vote, is taking part in a final set-piece TV encounter.
Speaking earlier, radical leftist Jean-Luc Melenchon said the EU must change or France would leave.
Opinion polls suggest a tight race with some 30% of voters still undecided.
Ms Le Pen and centrist Emmanuel Macron are seen as frontrunners to progress to the second round.
However, Francois Fillon of the centre-right Republican party and Mr Melenchon are also in the frame.
The candidates drew lots to establish the order of speakers, with Mr Melenchon coming first. Each candidate is being interviewed individually for 15 minutes.
‘Change or leave’
As she delivered her line about keys, Ms Le Pen dangled one before viewers.
She called for withdrawal from the euro “to restore competitiveness”.
On terrorism, a major concern for France after attacks claimed by so-called Islamic State, she said “hate-preaching imams” and foreigners who are on a police security watch list should be expelled.
When Mr Melenchon was asked if France should leave the EU, he replied: “We change it or we leave it.” He said he believed in an “independent France orientated towards peace”.
Asked about his controversial tax plans, he said: “We are actually going to tax incomes above 400,000 euros [£335,000; $429,000] a year at 90%”.
French election: Candidates turn fire on EU in last TV pitch