This is a French hard paste porcelain veilleuse, or demitasse warming teapot. The age is the middle of the 19th century, circa 1850.
The veilleuse is in four parts, the base, the teapot, the lid to the teapot and the small tray that holds the warming candle. The teapot sits on top of the base, a candle is inserted into the base, and the candle keeps the tea in the pot warm. It is a demitasse teapot, intended to give one person one cup of tea.
The veilleuse is 10 1/4" high and 6 ½" wide at the teapot's spout-to-handle.
The candle light will show through the drilled holes in the base. One interesting feature of this veilleuse is that the bottom is rectangular, like a building, with an arch on the sides that matches the teapot, and the arch looks like a heart.
There are a few flaws that I show in photos. One, there is an old glaze chip or hole on the rim of the base. Two, there is a nick in the opening on the base, with a stress crack radiating around the side. Three, this one you can't see in the photos at all, but there is a horizontal line in the glaze that goes over the top of the lid, not a crack, but a line in the glaze and it is perfectly straight. And of course there will be old tea stains and aging related dirt smudges. Old veilleuses that are available for sale in the antique market have flaws because they were loved and used, and were not intended for display only.
The number 615 is impressed into the bottom under the glaze.
You can read about veilleuses in the book "Veilleuses A Collector's Guide" by Harold Newman. Be sure to visit the other veilleuses I have listed in my shop as I do showcase a few of the more rare pieces.