At the ceremony in the revamped Eltz Castle, Josipovic described Vukovar as a symbol of peace, which was why such a centre should be built there.
Vukovar Mayor Zeljko Sabo said that the centre would be a meeting point for students from all over the world wishing to learn skills of peace and tolerance.
Japanese Ambassador Masaru Tsuji expressed hope that the stone and the brick from Hiroshima and Nagasaki would remind the centre's visitors of the need to build peace and of the tragedy of wars.