Lovely little brass piece of history. This little Parisian case would have been carried in early unheated cars at the turn of the century. Hot coals would have been put inside and the heat regulated by sliding the vents. Perfect for warming hands or feet. 
This has a particularly lovely design, as a Parisian special model. At over 100 years old, there are signs of age and use, it's a bit wonky and a bit rusty inside but that's it's charm and authenticity.

It measures 14cm 5.5" x 19 7.5" x 5cm 2"

French antique brass boudoir warmer from Paris