The complaint, filed Tuesday in The Hague, follows a ruling by Italy's top criminal court ordering Berlin to pay euro1 million (US$1.4 million) in damages to nine relatives of victims of a June 1944 massacre in the Tuscan town of Civitella.
In the atrocity, German soldiers killed more than 200 civilians to avenge a deadly attack by partisans.
In its filing with the World Court, Germany argued that as a sovereign state it has immunity in Italian courts, and that any decision rendered in the Italian judiciary is unenforceable.
Germany, which says it has paid reparations for Nazi crimes under international treaties with Italy, rejected the ruling handed down by Italy's Court of Cassation two months ago.
German Foreign Ministry spokesman Jens Ploetner said seeking compensation for World War II crimes was "morally understandable but it is, in judicial terms, the wrong way to address this injustice, and so this ruling is not acceptable for us."
Compensation claims against Germany have been winding through the Italian judiciary since the late 1990s, when Luigi Ferrini sought restitution for his arrest and deportation to Germany in 1944 to work as a slave laborer in the Nazi armaments industry.
Germany fought the case, pleading immunity. Ferrini lost in two lower courts before the Court of Cassation overturned the previous decisions in 2004 and recognized Italian jurisdiction.