Reliquaire-monstrance
France, XIVe siécle ou début du XVe siécle (avec adjonctions de la seconde moitié du XVe siécle ou du XVIe siécle)
Argen t partiellement gravé et doré, verre
Legs Mme Piet-Lataudrie, 1914
Cl. 19967

Which can be roughly translated as:

Reliquary-monstrance
France, 14th century or early 15th century (with additions from the 2nd half of the 15th or 16th century)
Engraved and partially gilded silver
Bequest of Ms. Piet-Lataudrie, 1914
Cluny catalog number 19967

More information on reliquaries can be found at Wikipedia and at the Metropolitan Museum of Art site.