Delete 'Supermarket', insert 'Hypermarket'.
Carrefour, Mammouth, Rallye... I remember them all from regular trips to France in the 1970's... They were simply GIGANTIC by comparison with even the largest British Supermarkets.
-Of course Wal-Mart's expansion and global encroachment has more recently recalibrated everyone's sense of scale, but in this case, I think it's probably safe to say that the French probably did it on that scale sooner than most others...
Keith