They're going to the Tintin museum in La Louvière?
They'll love it. The building itself is worth the visit.
Little gifts? Difficult to say.
I'd stay away from the typical tourist gifts (you know those shops you can find in any city that attracts tourists). There's a lot of tacky things involving Manneken Pis, which I would avoid.
You can go for "lace
" because Belgium is known for lace. The problem with that is that Belgian-made lace is expensive. Most of the lace sold is made in low wage countries. My german sister is in the USA for 3 months and she asked me to buy some home-made lace. There's a shop on the Grand Place of Brussels where you can buy some but you'd have to ask for Belgian made lace. You basically have 2 types of Belgian lace: Brussels style lace and Brugge style lace.
Antique lace is beyond expensive. However, you can still buy lace that's recently made in Belgium for a reasonable price. I bought my sister a piece of lace to put on a coffee table for about € 50.
(lace is not really my thing, but some people love it)
If they want to buy food
other than chocolate. Belgians love their food, but I'd go for speculoos
. It's easy to take with you in your luggage, it doesn't melt. This shop (link) is in the heart of the city and it has a very good reputation. Apparently, their speculoos is otherwordly. (I'm ashamed to say that I haven't tasted it, although I LOVE speculoos).
I don't know if you're fond of (hand)bags
but one of the advantages of living in Belgium is that we have more than our fair share of exquisite bags.
They go from the affordable (Kipling is quite known worldwide and it's Belgian, there's a Kipling store near the Grand Place on the Grasmarkt, if I'm not mistaken) to the more expensive (Nathan Baume, Yves Renard
) to the outrageously expensive (Delvaux
Brussels has a lot of flea markets and antique shops
. They can visit the flea market where Tintin found that ship that features in the Spielberg movie.
The best antique shops + that Tintin flea market are in the Zavel area (petit Sablon/kleine Zavel) which is also in the historic area of the city.
On the "Grasmarkt", which is also near the Grand Place by the way, there's a shop "The Brussels Corner"
where you can buy a lot of "I love Brussels" stuff. It sounds tacky as well, but they actually have some nice things.
(incidentally, there's a beer shop right next to it)
The Dansaert area
is the more artsy area where you can find designer stuff and the more original concept stores.
There's a "Museum of Belgian Comic Strip"
in Brussels. The building itself is another gem in the Art Nouveau style. It's been ages since I visited it but I remember it having a very cool shop. I was like a kid in a candy store when I saw that shop.
Online guide to shops in Brussels
If they're looking for diamonds
, they need to go to Antwerp but the more expensive diamonds are in safe areas anyway (so not the typical shopping Streets)