There are a couple supermarkets that are closer to my apartment/more conveniently located for me…read morethan this Carrefour Market (including a Franprix, a Naturalia, and a couple Carrefour City locations), but for my weekly shops, I usually choose to make the walk to this Carrefour Market location because I've found it has the best selection for affordable grocery shopping.
This market has a wide variety of products, ranging from produce, meat, snacks, and shelf-stable food to household cleaning supplies and even some small kitchen appliances (although these are limited to kettles, toasters, and similar). I don't have a lot of space in my kitchen so I often opt for frozen pre-cut vegetables, and this Carrefour has a great selection of these, including stir-fry mix, vegetables for making soup, spinach, bell peppers, and sweet potatoes. Basics are very affordable, including canned lentils, rice, pasta, and bread.
Before making a trip home to America, I wanted to bring some French items back for my parents; things like financiers and madeleines were super cheap and the individually wrapped ones were handy for distributing among friends/family. The Carrefour brand items are great for everyday, but if you want something "fancier," you can also find more gourmet versions of dried sausages, foie gras, and biscuits at this location too.
There's a pretty big organic/bio section, including bulk goods if you prefer to shop low waste (I think in general these are slightly more expensive per kilo than buying cans, but still very affordable). You can also get "ethnic" items here such as coconut cream, "Mexican" spice mix, and curry, although I find the options to be less varied than in America (I expect this is common throughout France and Europe, though).
Since the store is pretty big, they've got a lot of check-out lanes, including multiple self check-out stations for customers with 10 items or less, so it's possible to get in and out pretty quickly, even during busy evenings. I do sometimes find the store a little hard to navigate--there's 2 separate freezer aisles so I often wind up at the frozen desserts when I'm actually looking for frozen vegetables, and if you make a wrong turn upon entering you just wind up at the self check-outs--but they seem to have made efficient use of the space available. This Carrefour location is conveniently located near lots of restaurants, boulangeries, and cafés, and would be easily accessible from metro stops on both Line 1 and Line 2.