“The Final Act was ready on 8 June. It was to be signed by the eight signatories of the Treaty of Paris and subsequently acceded to by all the other parties concerned. The plenipotentiaries of the Eight gathered for the purpose on the evening of Friday, 9 June in the great reception hall of the Hofburg, in the presence of all the contracting parties. It was the first and only time the congress had assembled in full, and its only corporate action was to listen as the text of the Final Act was read out.
Cardinal Consalvi would not sign it, and instead delivered himself of a denunciation of the congress for having failed to return to the Pope his French fiefs of Avignon and the Comtat Venaissin and the city of Ferrara. Labrador also refused to endorse the proceedings, in protest at the arrangements reached in Italy. Nesselrode professed his eagerness to sign, but warned his colleagues that he could not do so until Alexander had read the document himself. He therefore raced off post haste to headquarters while the others appended their signatures and their seals, and the document was not finally signed by all until 26 June. By that time a war had been lost and won.”
— Rites of Peace: The Fall of Napoleon and the Congress of Vienna by Adam Zamoyski