France and Germany are marking the 50th anniversary of Elysee Treaty that helped to reconcile the two former foes.
The German and French leaders have been holding talks in Berlin and there will also be a joint session of the two countries’ parliaments.
Despite ups and downs in the relationship, Berlin and Paris have been key shapers of the European Union.
Charles De Gaulle described Europe as “a coach and horses, with Germany the horse and France the coachman”, and the co-operation between the two nations has been the foundation stone of the European project.
To celebrate what has been described as a festival of friendship, France and Germany are issuing stamps, coins and other items of memorabilia.
French flags will be flying beside those of Germany in Berlin.
Later on Tuesday, more than 500 French lawmakers will travel to the German capital for the session with the Bundestag.
There will also be a joint cabinet dinner and a concert.
Angela Merkel said in her weekly podcast on Saturday that she felt “a very great closeness” with Germany’s neighbor.
“When we have come together, then mostly a good new solution has come out of it,” Angela Merkel said.
However, the two countries remain at odds on several issues, including how to deal with the eurozone crisis.
President Francois Hollande – who is pushing for fresh spending to bolster growth – believes that the Germans are wrong to place such emphasis on austerity and cutting deficits.
On Francois Hollande’s side there is also still bitterness that Chancellor Angela Merkel backed Nicolas Sarkozy so openly during last year’s French presidential elections, our editor says.
The ongoing crisis in Mali is also likely to test the two countries’ relationship.
While Paris has deployed troops in West African nation to halt the advance of Islamist insurgents, Berlin has been reluctant to be drawn deeply into the conflict.