This is a bronze cast portrait medal of John Lemoinne by Juliette Dubufe, France.
John Lemoinne, 1815-92, was a French journalist and politician, active from 1840 specialising in Anglo-French matters.
Juliette Dubufe 1822-1855 was a French sculptor. She was the daughter of Joseph Guillaume Zimmerman, a musician.
She married Édouard-Louis Dubufe in 1842 and had two children (the son was a good painter), but she died in childbirth in 1855.
I have only traced two medal portraits that she made, of which one was dated 1846, but very similar in style.
150mm. in diameter, fine cast with founder’s mark on back.