any hardware on covers is gone. 

wear and use

missing plates from inner covers? 

fair? shape.

This is a 19th-century "Paroissien Romain" (Roman Parishioner) prayer book published by Morizot in Paris.It is a "diamant" (diamond) edition, a term often used to describe exceptionally small, compact prayer books.The text is provided in both Latin and French, covering Sunday offices and major feast days.The publisher, Morizot, was located at 3 Rue Pavée-Saint-André-des-Arts, as seen on the title page

1850 is a guess