This truly is an exceptionally beautiful piece. A French creamy white porcelain benitier or Holy Font made by premier manufacturers Sarreguemines, stamped and embossed on the reverse. 
The clarity of the detail and superior manufacturing techniques of Sarreguemines set this treasure apart from others I have seen. 
It is in super condition and was maybe hanging in a lady's boudoir as it is so delicately and beautifully patterned.

There are two holes above the cross for it to be hung in the wall.

It measures approximately 7" long by 3" wide at the cross. 

The Napoleon III ebonised frame it is pictured inside is for sale separately.  

Exceptionally fine French antique porcelain Holy font or benitier