The full title of the French publication is "Briefve relation de la notable conversion des personnes royales et de etat de la religion chrétienne en la Chine".
This is the account of Michael Boym about the situation in China and at the court of Emperor Ming Yongli about the conversion of the court recited by him in the church of St. Michael in Smyrna (now Izmir, Turkey) on September 20, 1652, and published in Paris by Seb. Cramoisy et Gabr. Cramoisy in 1654.
A link to the 1654 French edition can be found here.