PARIS, Nov.11 -- With world leaders gathered, church bells rang and Bach's Sarabande played, French President Emmanuel Macron on Sunday held a solemn ceremony to mark the centenary of the Armistice of the First World War.

Around 11 a.m. local time (1000 GMT), Macron and delegates from around 70 countries walked side by side towards the Arc de Triomphe to pay tribute to around 10 million soldiers killed during the 1914-1918 war.

In a wintry and rainy day, 40-year-old Macron inspected troops. In his following speech, the president reminded the gathering that "during these four years, Europe had come close to committing suicide. 10 million dead, 6 million injured," ringing an alarm bell for the rising nationalism, which, according to him, would put on edge fragile world peace.

100 years on, the French president warned "the old demons are rising again. New ideologies manipulate religions, history threatens to resume its tragic course.

"Let us build our hopes rather than playing our fears against each other," he said.

"The lesson we draw of the great war cannot be rancor and resentment against other nations. And it cannot be allowing the past to be forgotten. The great war is a foundation that obliges us to think forward to the future and think of our essential values," he noted.

At Sunday's commemoration, young students, born decades after the World Word II, read out in English, Chinese and French etc. testimonies written by French, German, British and American soldiers when the guns fell silent on Nov. 11, 1918.

Culminating a week of World War I memorials, Macron also lighted a flame and laid a wreath to honor an unknown soldier who was killed in the war and whose remains are buried with others under the arch.

After the ceremony, Macron hosted a lunch for the heads of state and government joining the ceremony. They then headed to the first Paris Peace Forum, without such leaders as U.S. President Donald Trump who attended the American commemoration ceremony at Suresnes Cemetery.

In his opening remarks, Macron said whether the image of the commemoration is a symbol of durable peace between nations, or a picture of a last moment of unity before the world goes down in new disorder, "it depends only on us."

He said that world's stability is threatened by nationalism, racism, antisemitism and extremism.

It's also challenged by economic, environmental and migrant-related factors, he said.

Following Macron's speech, German Chancellor Angela Merkel made references to serious conflicts worldwide, saying if "we believe that we have to draw conclusions from and learn from history, that makes us speechless."

"We must not accept armed conflicts, wherever they are in the world, no matter how far away, no population, no nation, not a single person must be written off by us, " she said.

Meanwhile, Antonio Guterres, secretary general of the United Nations, told the forum that many elements today appear to resemble the beginning of the 20th century and the 1930s, warning against "a polarization of political life and of society itself."

Guterres championed the cause of United Nations in his speech, saying today it is home to the center that harmonizes efforts towards peace and sustainable development.

The forum is organized around five themes: peace and security, environment, development, inclusive economy and new technologies and will last three days.

Starting from July 28, 1914, and ended on Nov. 11, 1918, the First World War is one of the bloodiest wars in history. Involving five European empires and dozens of world powers, it ended up with a Europe left in ruins and almost a generation of youth depleted.