French presidential candidate Marine Le Pen is facing accusations of plagiarism after a speech she made resembled parts of an address delivered by her defeated rival Francois Fillon just two weeks earlier.
He led an annual march from the statue of the legendary French heroine and FN nationalist icon Joan of Arc to the Paris Opera house.
French independent centrist presidential candidate Emmanuel Macron.
If the next day I decide to take actions and continue the current functioning of the European Union, I would betray my people.
Cazeneuve also reiterated his call to vote for centrist, front-runner Emmanuel Macron in the decisive, May 7 run-off vote against Le Pen.
He said: "She is not Joan of Arc but she accepts the same mission".
With six days to go before the second round of the presidential election that polls show him on track to win, Macron made the pledge at a rally of around 12,000 people on the edge of Paris. That has fed speculation that a high abstention rate could favour Le Pen, whose supporters typically tell pollsters they are staunchly committed to their candidate.
"What the National Front candidate proposes is a one way ticket".
France votes for a new president on Sunday, a ballot being watched closely by financial markets and France's neighbors as a test of the global populist wave.
In a feisty speech, Macron told thousands of his supporters he would defend "free democracy" if voters choose him on Sunday after Le Pen had urged voters to reject "the world of finance, of arrogance, of money as king" she said her opponent embodied.
CGT leader Philippe Martinez said he "deeply disagreed" with that approach, arguing that Le Pen and Macron "are not the same thing". The death drew national outrage. "Because the day after, we will have a Frexit or we will have [Ms Le Pen's] National Front (FN) again".
Said, a chauffeur who supports Mr Macron, said his father was targeted "because he was a foreigner, an Arab. That is why I am fighting, to say no to racism".
Under a deal struck Saturday with euroskeptic Nicolas Dupont-Aignan to attract the 1.7 million votes he garnered in the first round vote, Le Pen said abandoning the euro was not a "prerequisite".
As many as 9,000 police officers were expected to be on the streets in Paris to cope with other rallies by anti-fascist groups, those who reject both candidates and Front National founder Jean-Marie Le Pen, who was expelled from the party by his own daughter, staging his own march.
This story has been corrected to show that Macron joined the victim's son, not his father.
Meanwhile, the traditional May 1 union marches across France will be politically charged this year.
Taking to the stage in Villepinte, Ms Le Pen declared: "Emmanuel Macron is François Hollande who wants to remain (in power)".