The 'C' couronné poinçon was a tax mark employed on any alloy containing copper between March 1745 and February 1749.
The form of these candlesticks is based on a drawing by Juste-Aurèle Meissonnier which was engraved by Huquier and published in Le Livre de chandeliers de sculpture en argent, folios 31 and 32, plates 73 and 74. The elegant swirling form and naturalistic motifs exemplify the early stages of rococo design in France and a pair of this design was first supplied to the French royal family on the occasion of the birth of the Dauphin in 1729.
A closely related pair of candlesticks is in the Wrightsman collection, New York (ill. F.J.B. Watson, The Wrightsman Collection, vol. II, Greenwich, 1966, cat. 164).
For a full discussion of this model, see P. Fuhring, Jules-Aurèle Meissonnier: Un génie du rococo 1695-1750, Turin, 1999, vol. II, pp. 193-197.