Representatives
On the papal side (the papacy being held at this moment by Pope Pius VII) was cardinal Ercole Consalvi, who had already negotiated the 1801 Concordat and was designated the plenipotentiary for the 1817 negotiations. On the French side, Louis XVIII chose his ambassador to Rome and favourite, the Comte de Blacas, who has previously served as the Prime Minister of France.
Read more about this topic: Concordat Of 11 June 1817