I found a British Iceland Supermarket Chain equivalent in France. (Mentioning it as if I am the first person to identify their similarities)

Picard specialises in Frozen Food and have a variety of ready meals and a wide choice of Frozen food. Unlike Iceland which sells fresh items as well, Picard is 99.9% frozen stuff.

I come here for Frozen mango cubes for My Poke Bowl (My kids love them!) They also have a wide variety of Asian Dim Sum. (although I get them cheaper from Asian Supermarkets but it is convenient as the closest store is only less 5 minutes for me).

If you plan to shop here, it is worth registering for their loyalty card which gives you discount to some members only offer.