Count Cavour and Napoleon III meet "by chance" at the southern French spa of Plombières-les-Bains and negotiate a secret treaty. The plan involves the goading of Austria into a war with Piedmont that France will then enter as the Italian state's ally. In return, the French are to increase their influence with the Pope and gain areas in south-west Italy, including Nice. Though not all will go according to plan, the war will arrive and France and Piedmont will defeat Austria and France will receive its new territories.
Source Citation
Michael G. Fry, Erik Goldstein, Richard Langhorne, Guide to International Relations and Diplomacy (New York: Continuum International Publishing Group, 2002), 123-124.