French President Francois Hollande and German Chancellor Angela Merkel are marking the 100th anniversary of the battle of Verdun, the longest of World War One.
Hundreds of thousands of French and German soldiers died during 10 months of fighting in north-eastern France.
France eventually emerged victorious.
But today Verdun is seen as a symbol of Franco-German reconciliation, which was reflected by both Mr Hollande and Mrs Merkel in their speeches.
The ceremonies started with the leaders visiting the German military cemetery at Consenvoye, just north of Verdun, where 11,000 German soldiers are buried.
The leaders then moved on to a ceremony at Verdun city hall.
In her speech there, Mrs Merkel said: “Only those who know the past can draw lessons and build a good future.”
Remembering the famous 1984 image of former leaders Francois Mitterrand and Helmut Kohl holding hands at Verdun, she said: “We have reconciled and reached agreement; we have become friends.”
Mr Hollande also reflected on Franco-German relations, saying that Mrs Merkel’s presence showed that Verdun was not a symbol of suffering but one of hope.
He said: “Verdun… is where Europe lost itself, 100 years ago. But it also experienced the best – the town was capable of galvanising itself, coming together for peace and for Franco-German friendship. Long live the spirit of Verdun.”
The main commemorative ceremony will be at the Douaumont Ossuary in the afternoon.
It focus on educating young people, and involve some 4,000 French and German children in a performance choreographed by German filmmaker Volker Schloendorff.
Church bells will sound throughout the Verdun area.
Some 60 million shells were fired during the battle. About 25% failed to explode, meaning that housing and farming in the battlefield area are still banned.
The battle of Verdun, 21 February – 15 December 1916
- Verdun – a strong point on the long front line dividing the French and German armies – was the longest battle of World War One
- At the end of the bloodshed in December 1916, France won back nearly all the territory it had lost in February
- General Erich von Falkenhayn, the Chief of the General Staff and Germany’s principal strategist, targeted Verdun because of its position on the Allied line and its sentimental value to French people
- Falkenhayn hoped to combine the Verdun offensive with a U-boat offensive against British shipping – the two campaigns together were designed to force France and Britain to seek peace terms
- But Falkenhayn’s plan for an attack that would economise on German resources failed to work out as he expected, and he used many more divisions than planned
- Germany, like France, accumulated huge losses and gained little territory, leading it to throw more and more men into the conflict, and Verdun soon became a battle of prestige for the Germans, as well as the French