Three-hundred-thousand soldiers were killed in the 300-day battle, the longest of the First World War.
Its commemoration has come to signify the reconciliation between Germany and France after the decades of hostility and distrust following two world wars.
In pouring rain, the leaders of France and Germany stood silent after laying a wreath at the German military cemetery, just north of the town of Verdun.
There, the remains of around 11,000 German soldiers are buried.
The battle -- a war of attrition lasting 10 months -- pitted the French army against the Germans, who tried, unsuccessfully, to break French defences around the town.
German Chancellor Angela Merkel said the town's name stands for incomprehensible cruelty.
"Verdun doesn't let us go, Verdun cannot and must not let go of us. Verdun as such stands for the cruelty and senselessness of war."
Such was the ill-feeling between the two countries over the battle that it took nearly 70 years for the countries to reconcile and hold a joint commemoration.
(Former President) "Francois Mitterrand and (former Chancellor) Helmut Kohl came to Verdun in 1984 to commemorate the dead, hand in hand. And this image embedded itself deeply in the memory of our two nations. This image illustrated the words that both heads of state declared on behalf of all of us: 'We were reconciled, we came to an agreement, we became friends.'"
The present French and German leaders then jointly lit a flame in a memorial building that contains the bones of many of the soldiers.
Germany and France are widely seen as the leading drivers of the 28-nation European Union.
But the EU is currently facing challenges including the massive influx of migrants and refugees, plus financial crises in several member states, and youth unemployment.
President Hollande outlined what he called particular responsibilities of the two countries.
"The responsibility to end conflicts on our doors, and that is what we have done, side by side, dear Angela, for Ukraine in the Normandy framework. Also, the responsibility to fight, for the respect of rights and freedoms, against terrorism, fanaticism, radicalisation. The responsibility, also, to welcome populations who are fleeing massacres and who are looking for shelter where they think they will be welcomed with dignity."
The potential exit of Britain from the European bloc has added to a widespread feeling that unity in the European Union is under threat.
"Our sacred duty is written in the devastated soil of Verdun. It is only a few words: Love our homeland, but protect our common house, Europe, without which we would be exposed to the storm of history. We know perfectly well that the time needed to destroy it would be much shorter than the long time it took to build it."
