“ After the meeting at Plombières between Cavour and Napoleon III. Nigra was sent to Paris again to popularize a Franco-Piedmontese alliance, Nigra being, as Cavour said, “the only person perhaps who knows all my thoughts, even the most secret.” He was instrumental in negotiating the marriage between Victor Emmanuel's daughter Clothilde and Napoleon's nephew, and during the war of 1859 he was always with the emperor. ”