Piano and furniture valuations

For the piano you could try here : www.hanlet.be
They do piano repair and service, as well as sell second hand piano's, and if they can't help they'll at least be able to point you in the right direction.

For the furniture

- "Old furniture" is in almost all cases worth essentially nothing. Try Freecycle, or offering it to your friends.

- "antique furniture" - you need to find a specialist but try wandering around markets like the Sablon or Place du Jeu de Balle till you see similar stuff to yours and see what they're selling for. Take those prices and divide by 2, that's the top end of what you could probably get if you're a good negotiator.