The settlement paves the way for the closing of a sale of Atlantia's stake in its motorway unit Autostrade per l'Italia to a consortium led by state-lender CDP.
A road bridge operated by Autostrade collapsed in the northern city of Genoa on Aug. 14, 2018, killing 43 people and triggering a legal battle.
In a statement, Atlantia confirmed it would pay 3.4 billion euros to settle the motorway contract dispute.
Atlantia, controlled by the Benetton family, also said it had been told it would not have to launch a bid on Autostrade Meridionali as a result of the settlement deal.
(Reporting by Stephen Jewkes, editing by Elisa Anzolin)