Marine Le Pen has told voters in the French presidential election she will "put back the borders" if she wins as she attempts to pull ahead.
The leader of France's National Front pledged to restore her country's "four sovereignties" as she held a rally with just less than a week to go before first round voting.
Ms Le Pen is struggling to hold the lead she held in the polls until around a month ago when centrist Emmanuel Macron pulled level.
However both of those candidates are facing a growing threat from left-winger Jean-Luc Melenchon, whose support in the polls has gone from barely 10% to nudging 20%.
As Ms Le Pen spoke, dozens of protesters clashed with police outside the entertainment complex in Paris where her rally was taking place.
Ms Le Pen told her rally: "The European Union is imposing double trouble on us: the lack of physical borders with the irresponsible Schengen Treaty.
"We got rid of our physical borders and that turned our countries into train stations for all immigrants around the world. I will end Schengen and restore our national borders.
"No other candidate is proposing this, none of them."
After the rally, Le Pen supporter and MP Gilbert Collard claimed he and his wife had been attacked during the protests and he had been hit by a petrol bomb and a beer bottle.
"Resistance, resistance"
Presidential election candidate for the leftist coalition La France Insoumise Jean-Luc Melenchon speaks during a campaign rally at the Prairie de Filtres park in Toulouse. Picture by: Rondeau Pascal/ABACA/ABACA/PA Images
Mr Melenchon was greeted ahead of his Paris rally by chants of "resistance, resistance" from a few hundred supporters.
The 65-year-old political veteran, who leads La France Insoumise (Unbowed France), has unnerved some of the other candidates by surging from behind in the final stages of the campaign and threatening to reach the second round.
Referring in his speech to a recent Financial Times story that he spooks investors, he said: "I am very dangerous.
"They make up stuff every day. All their systems are built on fear. Keep the fire of rebellion burning inside you!"
Mr Macron held the biggest rally of his campaign in Paris on Monday, telling 20,000 supporters he was the only one of the 11 candidates who wanted to take France forward, rather than back to a "fantasy" past.
He said: "We need Europe my friends, so we will rebuild it... I will rebuild a strong and balanced alliance, thanks to you, with Germany in order to give back Europe a real dynamic."
The two candidates who score the most votes in the first round on Sunday will go through to the last round on May 7th.
In the latest poll released on Monday, Conservative candidate Francois Fillon was tied with Mr Melenchon, several points behind Ms Le Pen and Mr Macron, despite having been the early favourite to win overall.
Mr Fillon lost some support after media revelations he allegedly paid his wife and children from state funds for work that was never done.
The Socialist candidate Benoit Hamon claimed he was still in the race despite his potential vote share dropping to half of what it was two months ago.
"Things are evolving," he said on Europe-1 radio.
Although Ms Le Pen remains a favourite to progress past the first round of voting this month, polls have indicated she will face a challenge in the second round - especially if she faces off against Macron.
However, the polls suggest a much tighter gap in a potential race between Le Pen and either Mr Melenchon or Mr Fillon.
In the aftermath of Brexit and Donald Trump's surprise victory in the US, many have sounded notes of caution about the accuracy of opinion polls - with the Le Parisien newspaper earlier this year announcing they would not be commissioning any polls in the lead-up to the vote.
