Hi Jaume,
A bad news and a good news.
Bad news : I could not find such a mark in : Arminjon and alii,
Dictionnaire des poinçons de fabricants d'ouvrages d'or et d'argent de Paris et de la Seine : 1838-1875, Imprimerie nationale, 1994,
...but good news : I could find it in in the previous book written by this research team : Arminjon and alii,
Dictionnaire des poinçons de fabricants d'ouvrages d'or et d'argent de Paris et de la Seine : 1798-1838, Imprimerie nationale, 1991, p. 183, n° 01650.
This mark is the one of Jean CHEROUX : J C, a bee above, a star below. This is his first mark, between 1827 and 1854 ; he then took another mark (a bee, a star above this time) between 1854 and 1862.
This identification is consistent with the period suggered by the Mercury head.
Legend for notices included in Arminjon's books :
[number N]) : description of the Nth hallmark registered by French administration (underlined)
[number N]) : speciality of the workshop, according to the information given to French administration
[number N]) : legal place of the workshop (in Paris)
[number N]) : registration ("insculpation") date of the Nth mark by French administration
[number N]) : unregistration ("biffage") date of the Nth mark by French administration