Cate Blanchett wears a Cartier Tank

Across Blue Jasmine, Cate Blanchett's Jasmine clings to the trappings of a fortune that has already evaporated, and one of those trappings is the gold watch on her wrist. In this frame it reads as a rectangular case with a pale dial, worn on a brown leather strap and stacked alongside gold bangles.

That silhouette is a Cartier Tank. The French watch publication Montres de Luxe identified Jasmine's watch as a yellow gold Cartier Tank on a brown alligator strap, and the costume writeup at Feather Factor describes the same gold Tank in her wardrobe, so two independent sources land on the model. Neither names the exact Tank reference and the dial is soft here, so the precise variant stays open. If you can read it from a cleaner still, please tell us in the comments.