Jae Z.
Yelp
In general, I'm not a big fan of department stores - there's usually too much muck to weed out. However:
This is my favorite department store in Paris. If Printemps is Bergdorf, Galerie Lafayette is Saks/Macy's, then Bon Marche is like Barney's except with an amazing food market complete with an epicerie, charcuterie, boulangerie, patisserie, marche, fromagerie, and various traiteurs. Individually, not all the counters are the best of the best, but collectively, this market is every pinky raising foodie's wet dream (Galerie Lafayette's top floor food market comes close but it's way crowded and I hate navigating through GL.) The macarons at the patisserie counter were miserable though, just a note. You just can't not love a dept store that has a food market on the first floor instead of makeup and perfume.
Another reason why Bon Marche is so favored: it was here that I made the best purchase of all time - a navy blue padded Givenchy nightingale at 50% off, plus a VAT refund, for which Bon Marche has a service on the top fl (rare, and so so convenient, I recommend taking the cash, less the handling fee, on the spot, because the airport VAT agents will also take a handling fee and it's a bigger hassle. Plus, if you travel elsewhere in Europe and fly back to the US from an airport in another country, you may not be able to get the VAT back altogether).
In terms of shopping in Paris, if you visit in July or January, you will not find better deals anywhere else in the world, especially at department stores. Even if its American counterparts stock the same brands, the Paris stores usually have better selection, because ...well, American dept stores cater to conservative (read: bland) American taste. As far as department stores go, Bon Marche is the most well edited I've seen. Basically, kind of epic.