French President Emmanuel Macron was set to host German President Frank-Walter Steinmeier in the eastern city of Strasbourg on Sunday to mark the end of World War I 100 years ago.

The two presidents are scheduled to attend a concert together in Strasbourg Cathedral featuring the German composer Ludwig van Beethoven and French composer Claude Debussy, which also celebrates the return of the surrounding Alsace-Lorraine region to France.

Alsace-Lorraine - known in German as Elsass-Lothringen and since 2016 subsumed into France's new Grand Est (Great East) region - became part of Germany after the Franco-Prussian war in 1871. Its return to France in 1918 was considered a restoration of national pride.

World War I was largely fought on French soil with the trenches dug in along the Western Front in the east and north-east of the country. Many people lost their lives in the Alsace-Lorraine region.

Almost exactly a year ago, Macron and Steinmeier recalled the mass killings in the 1914-18 Great War when on a mountain in the Vosges range near the Alsatian city of Colmar they opened the first Franco-German museum to commemorate the deaths of millions of soldiers.

The war remains a delicate subject: besides German aggression and atrocities, there is the prickly subject of 60,000 German residents who left the region after the war, some of their free will, but many driven out.

"That was a real bloodletting," historian Franck Burckel from the Strasbourg city archive told dpa.

The region was again occupied by Nazi Germany in 1940, but has since come to symbolize the reconciliation between the two countries, now close EU partners.

It is not complete harmony between the two neighbours: Germany has been a harsh critic of the ageing nuclear power station in Fessenheim to the south of Strasbourg, which it sees as a security risk and would like to have shut down.

After the concert, Macron plans to set off on a commemorative marathon, through 11 departments in the east and north of his country, to prominent places during World War I, including Verdun and Reims.

On November 10, the president plans to meet German Chancellor Angela Merkel in Compiegne in the remote forest clearing where a century ago, early in the morning, the WWI truce was signed in a converted dining car.

The crowning glory of the commemorations will be a meeting of some 60 heads of state and government on November 11 in Paris.