Paris: French President Francois Hollande will underline the need for European unity at a ceremony on Sunday in Verdun to honour those killed in one of the bloodiest battles of the First World War 100 years ago.

To mark the centenary, Hollande and German Chancellor Angela Merkel will lay wreaths at cemeteries holding the dead of both sides in the northeast French town.

The 1916 offensive lasted 300 days and claimed more than 300,000 lives.

Hollande will emphasise the need for joint action at a time when the European Union is under pressure from the migrant crisis and a possible British exit.

In the run-up to the ceremony, he recalled the moment during the 1984 commemoration that his predecessor Francois Mitterrand and the then chancellor of West Germany Helmut Kohl joined hands during the playing of the French national anthem.

“Mitterrand’s gesture with Helmut Kohl, the hands that reached out and found each other, that’s the symbol of reconciliation,” he told French radio this week.

Now was the time for both countries’ leaders to spell out what they wanted to do for Europe at this moment, a time when the continent was in the grip of the “evil of populism”.

That appeared to be a reference to Europe’s far-right parties, which have made advances in several countries. In Austria last Sunday the anti-immigration Freedom Party candidate missed winning the presidency by the narrowest of margins.

Underlining his drive for European unity, European Commission President Jean-Claude Juncker will also attend Sunday’s ceremony.

Brexit looming

Hollande and Merkel will start by visiting the German military cemetery at Consenvoye, just north of Verdun.

At a lunch Sunday the two leaders will then discuss the crisis caused by the hundreds of thousands of migrants and refugees seeking refuge in Europe and the June 23 British referendum on whether or not to quit the European Union.

Both leaders will give short speeches that will touch on the current challenges facing Europe.

Then they will attend a ceremony at the Douaumont ossuary, where the remains of 130,000 soldiers, French and German, lie underground.

It was here that Mitterrand and Kohl made their symbolic gesture to reaffirm Franco-German friendship, in September 1984.

Sunday’s ceremony at Douaumont will also feature more than 3,000 children from France and Germany in a presentation choreographed by the German film-maker Volker Schloendorff.

Church bells for miles around will ring out in memory of the soldiers who died on both sides.

But preparations for this year’s ceremony were marred by a row over a concert due to be given by Black M, a popular rapper in France who is accused of writing anti-Semitic and homophobic lyrics.

Verdun mayor Samuel Hazard cancelled the gig, joining critics who said an appearance by a man who describes France as a land of “unbelievers” was an insult to the memory of those killed.

But the minister for war veterans Jean-Marc Todeschini accused the mayor of giving into pressure from the right and the far-right.

Those who fought and died in Verdun came “from all social backgrounds, from all continents, of all religions,” he said.