If you live in the Mons area or are visiting Mons with kids, Maubeuge can be an alternative to the more famous Pairi Daiza zoo in Brugelette. It is only about 30 minutes drive from Mons, right at the border, and allot cheaper to get into. My son went there with his class, at school, and he made me curious.
Inside, they have a pretty large number of species and their enclosures are decent. I loved walking inside as the pathway is flanked by tall bamboo grass making it look like you are in a bamboo forest.
They house a white Bengal tiger who was too lazy to get up so we can get a better look. The lamas' habitat is open to the public so you can walk around them, feed them form the food dispensaries, pet them.
A really neat place to spend a few hours during a weekend or, if you want to avoid the crowds, during the week.