PARIS- Far-right French commentator Eric Zemmour announced his candidacy for president on Tuesday with a video that depicted Black men and Muslim women and called on voters to take the country back "from minorities that oppress the majority".

A former journalist who has been convicted for inciting racial hatred, he becomes the top contender to challenge Marine Le Pen, leader of the more established far-right National Rally, for a place in a second round against President Emmanuel Macron.

His candidacy turns the election into a test of the endurance and limits of Europe's far right, which surged across the continent in the last decade but shows signs of reaching a ceiling as it pushes against boundaries of acceptable speech.

"For a long time I was happy with the role of journalist ... but I no longer trust that a politician will have the courage to save the country from the tragic fate that awaits it," Zemmour, 63, said in a video posted on social media.

"That's why I have decided to stand in the presidential election."

His hardline criticism of Islam and immigration has drawn support both from Le Pen's voter base and from the mainstream conservative right, but has also alienated some voters that Le Pen had long sought to reassure.

"We must give back the power to the people, take it back from minorities that oppress the majority," Zemmour said.

As footage showed women with headscarves and Black men in the metro, Zemmour told voters: "You feel like you are no longer in the country you once knew ... you are foreigners in your own country."

After a meteoric rise in opinion polls over the past weeks, with several surveys forecasting he would beat Le Pen to the election's run-off round, his popularity has been slipping.

At this stage, most opinion polls forecast that Macron and Le Pen will face each other in the second round next April, which Macron would be likely to win in a repeat of the election of 2017.

But Zemmour led Le Pen for a while in recent weeks, and the race for the number two spot is still neck-and-neck in some surveys.

"So far, it was a warm-up. The real race begins," said an email by a spokesperson for the "Friends of Eric Zemmour," sent to his supporters.

Zemmour's campaign has been stalling after various mishaps.

One was at the weekend, when he was photographed giving the middle finger to a protester following a tumultuous campaign stop in Marseille. He also sued gossip magazine Closer after it claimed he was expecting a baby with his chief political aide. 

Opinion polls also show he has shocked some voters with provocative comments - from saying children shouldn't be given foreign-sounding names to claiming that the French government which collaborated with the Nazis during World War II had protected Jews. And he has lost the backing of some high-profile supporters, French media say.

(Additional reporting by Elizabeth Pineau and Sudip Kar-Gupta; Writing by Ingrid Melander; Editing by Peter Graff)