Pierre Paul Cambon (20 January 1843, Paris – 1924) was a French diplomat and brother to Jules Martin Cambon.
He was called to the Parisian bar, and became private secretary to Jules Ferry in the préfecture of the Seine. After ten years of administrative work in France as secretary of préfecture, and then as prefect successively of the départements of Aube (1872), Doubs (1876), Nord (1877-1882), he exchanged into the diplomatic service, being nominated French minister plenipotentiary at Tunis, fulfilling two terms as Resident-General.
In 1886 Cambon became French ambassador to Madrid; was transferred to Constantinople in 1890, and in 1898 to London, where he served until 1920. In London, Cambon quickly became an important figure, helping to negotiate the Entente Cordiale between Britain and France in 1904, and serving as the French representative at the London Conference which resolved the Balkan Wars between 1912 and 1913. Upon the outbreak of the First World War, Cambon helped secure British intervention on the French side. He was decorated with the Grand Cross of the Légion d'honneur, and became a member of the French Academy of Sciences.