Claude Louis Jonquoy
Born: 8 Oct 1788, Paris, son of Claude Jonquoy & Marie Victoire Nicole Escur
Married: 15 Mar 1813, to Marie Madeleine Boissard
Died: 12 Mar 1861, Paris
He was a silversmith specializing in snuffboxes, and registered six marks between 1818/19 and 1846, the last being cancelled on 2 Feb 1849, when he retired and was succeeded by Edme Picard. His mark was CJ with a crown and one crescent above and two below (changing to two above and one below in 1846.)
Of (perhaps ghoulish) interest is that his father, Claude Jonquoy, a tablettiere, was a victim of the Terror, guillotined on 28 thermidor an II [14 Aug 1794].
Hope this helps!
Ref: Arminjon I:709