France is on high alert as demonstrators gather to protest the rise of far-right presidential candidate Marine Le Pen.

On the day that the Front National (FN) holds its annual gathering to celebrate the party's chosen heroine, Joan of Arc, more than 250 events across France are planned in protest. Demonstrations are planned for Toulouse, Nice, Marseille, Lille and Poitiers.

Union and political leaders in Paris will head up huge crowds expected to turn up at the capital's squares of Place de la Republique and Place de la Nation via Bastille.

Police authorities are concerned about possible lone attacks, similar to the incident at the Champs-Élysée in which a policeman was shot dead and two others were wounded.

More than 9,000 officers and soldiers will be on duty to stop and search vehicles as well as conduct identity checks on pedestrians.

The first event took place at 7.30am local time at the Palais Royal where FN's founder Jean-Marie Le Pen will lay a wreath on the statue of Joan of Arc, claimed by Front National as their heroine. His daughter Marine Le Pen has distanced herself from the event and is holding a rally at a Paris exhibition centre, according to AP. However, the presidential candidate recently tweeted: "Joan of Arc, this young shepherdess of modest origins, fought to give France her freedom. It's a model."

On France-2 TV, Marine Le Pen said the political distance between herself and her father is "is definitive". She called it a "violent" decision for herself, but said she did it "because the higher interest of the country was at stake". Last week, Marine Le Pen also said she has stepped back from her role as FN's leader.

Communist newspaper L'Humanité wrote: "Workers' Day will have a particular importance this Monday. Almost all unions have called for demonstrations not just to combat the FN but also to reclaim social progress during these marches." It added: "The unions are unanimously against the extreme right."

On Monday evening, current favourite to win, Emmanuel Macron, will attend a rally at Paris Event Centre in La Villette, in the eastern part of the capital city. On Sunday night (30 April) Macron told reporters that 1 May "is the face of a globalization that protects workers… an accomplishment of the great labor fights to defend worker rights".