The "Berlin Declaration" marks the signing on March 25, 1957, of the founding Treaty of Rome.
The new document sets 2009 as the deadline for preparing a new constitutional treaty, to replace the constitution which failed to win approval by voters two years ago.
In a speech before the adoption, German Chancellor Angela Merkel said that Europe could take none of its cherished ideals -- peace and freedom, democracy, and the rule of law -- for granted.
Germany currently holds the post of the rotating EU Presidency.
(AFP, Reuters)