France’s troubled wartime past has taken centre stage in a highly charged presidential race as Emmanuel Macron visited the site of France’s worst Nazi massacre and Marine Le Pen’s party suffered a new blow over alleged Holocaust denial.

Seeking the moral high ground, centrist Mr Macron wants to send a message to voters that Ms Le Pen is not a candidate like any other, but the heir of a party stained by anti-Semitism, racism and an outdated world view.

Her years-long efforts to detoxify her far-right party’s image have suffered a new setback as the leader of the National Front quit because of an uproar over past remarks allegedly questioning the Nazi gas chambers.

French emotions around a history of collaborating with the Nazis remain raw, seven decades after the end of the war. The country has never undergone a national atonement; and many people still view the actions of the collaborationist Vichy regime as a historical anomaly instead of atrocities committed by the French state.

Mr Macron sought to bring the horrors of the Holocaust home to voters with his visit to Oradour-sur-Glane, a ghost town left behind after the largest massacre in Nazi-occupied France. The town is a phantom village, with burned-out cars and abandoned buildings left as testimony to its history.

On June 10 1944, four days after the Allied D-Day landings in Normandy, an SS armoured division herded villagers into barns and a church, blocked the doors, and set Oradour-sur-Glane ablaze. A total of 642 men, women and children died. Only six people survived.

In comments to local newspapers, Mr Macron said: “We don’t want to forget that from here, from Oradour, comes our Republican pride, the National Council of the Resistance that has built our (fundamental) balances, our strength and the European project. That is everything Marine Le Pen wants to destroy.”

Ms Le Pen prompted an outcry earlier this month by denying that the French state was responsible for the round-up of Jews in the Second World War, in a reference to the Vel d’Hiv, the Paris stadium where thousands of Jews were transferred before being sent to Nazi death camps.

Interim National Front leader Jean-Francois Jalkh resigned on Friday over comments reported in a 2000 interview in which he allegedly cast doubt on the truth of Nazi gas chambers.

National Front vice president Louis Aliot said on BFM television that Mr Jalkh is stepping down to avoid further damage to the party, but that he is contesting allegations of Holocaust denial, a crime in France.

Mr Jalkh is among seven people called to trial in an alleged illegal financing scheme for the party – one of the other challenges facing Ms Le Pen’s campaign.

Mr Aliot said Mr Jalkh will be replaced as party leader by Steeve Briois, mayor of Ms Le Pen’s electoral fiefdom of Henin-Beaumont in depressed northern France.

Ms Le Pen is not letting setbacks deter her. She is painting herself as David against Mr Macron’s Goliath as she tries to overcome a poll gap and broaden her support base.

The two candidates offer starkly different visions of France’s future – Mr Macron’s embrace of a globalised, diverse nation within an open-bordered Europe vs Ms Le Pen’s protectionist, tightly policed France independent of the EU.

Ms Le Pen reached out on Friday from her far-right base across to the far left, urging voters who chose communist-linked Jean-Luc Melenchon in the first-round vote to support her in the run-off.

Ms Le Pen and Mr Melenchon won a combined 40% of the vote in the first round after populist campaigns that tapped into widespread frustration with mainstream politics.

While they hold opposing views on immigration and social issues, they are both sceptical of the EU, hostile to free-trade deals and promised to help workers hurt by globalisation.