New discovery !!! I found a Korean + Japanese supermarket in Paris. Rue Saint-Anne is very known as the Mecca of Sushi and Bibimbap area, there are gazillions of restaurants to choose from. Not forgetting their supermarkets as well if ever you feel the need to make home made sushi instead. But yeah, K-Mart is one of them.
Apart from selling groceries specialized for Korean and Japanese cuisine, they have this cutest little cantine where they sell fresh out-of-the-oven variety of dishes like Bibimbap, Onagiri and rice set, Miso soup, and many more. Ok, so they don't provide tables and chairs to properly eat your food.. :( But no worries, the food are hell cheap and you can easily eat at next door's Japanese boulangerie (that's what I did)
I bought a lunch set Onagiri and rice for 6,50€ ( no picture, I gulfed it down in a matter of seconds) and this bottle of pure Japanese Green Tea, WITHOUT SUGAR mind you for 1,50€.
K-MART, 8 rue Sainte-Anne (juste à côté de la caserne de Pompiers), à 200 mètres sur la droite en venant de l’avenue de l’Opéra, Paris 2e. 01-58-62-49-09.