I'm a bit late in posting a reply, but if your friend has already left for Europe, this might be helpful for future trips.
Belgium: Chocolate is definitely the No. 1 item. I would also suggest a tangerine liqueur called Mandarine Napoléon. There is no single orange-flavoured liqueur that provides quite the citrus intensity of Mandarine. Although it's not entirely unavailable in the US, it's frightfully hard to come by, and it is considerably less expensive there.
France: If you do much baking, I suggest a selection of your most frequently used flavouring essences. French distilled essences are top quality and far better than most of the ones available in the US--if they can be found at all.
The French essences I use are: fraises des bois, bitter almond oil, violettes, griottes or amarène (related to morello cherries), noisette/praline, framboise, and mandarine. You'll have your own favourites, of course.
In the US, La Cuisine in Arlington, VA carries a selection of French essences, but they aren't always in stock.
Hope all this helps.