French Marine Nationale smock, in a denim style fabric. Menswear XS size, would work like a UK a UK8/10. Early 1970s, as part of the official French Navy outfit.
 
Faded and worn, with a large paint stain on the back of the right sleeve - please see photos.

2 inside pockets. Large sailor style collar.

A great piece.

Any questions, please get in touch.