German President Frank-Walter Steinmeier on Saturday thanked the Italian migrants, once known as "guest workers," who helped rebuild Germany after World War II.

Italian guest workers made an important contribution to Germany's economic rise, Steinmeier said at a joint event with Italian President Sergio Mattarella in Berlin.

He said his country owed them gratitude and respect, not least because they often encountered prejudice and rejection in Germany.

"It took a long time for our country, for my country, to recognize the remarkable achievements of those people who came to us back then," Steinmeier said.

"That is precisely why it is so important to me today to make it clear once again: the success story of postwar Germany also has a background in migration," he added.

In December 1955, Germany signed an agreement with Italy that enabled hundreds of thousands of Italians to move to Germany to work.

These people did Germany a lot of good, Steinmeier said. "Not least because they helped us to become a little more Italian as a society. And I don't just mean in culinary terms," he joked.

At the event in Steinmeier's official residence, Bellevue Palace, the two presidents also honoured six German-Italian town twinning partnerships for projects in the areas of youth and intergenerational dialogue, civic engagement, remembrance culture, sustainability and social cohesion.

The prize, endowed with €200,000 ($230,000), "recognizes the role of local authorities and encourages local administrations to forge new relationships with other countries, thereby building a genuine network of local politics," said Mattarella.