Fritz and I were back in Brussels in July/August. Whenever I have been to Brussels in the past it has been cold and raining. This time we were treated to perfect weather. We checked out Parc du Cinquantenaire, which is dog friendly as the sign at the entrance makes clear.
Although the sign implies a leash law, we saw plenty of dogs off-leash so I suspect this is loosely enforced, as in much of Stockholm.
I've blogged about this before, but we always stay at the Sofitel Europa on Place Jourdan. They are very dog friendly - Fritz was provided his own bowel and bed. Also, they are convieniently located near Parc du Cinquantenaire and Parc Leopold.