As surprising as this may sound, finding a restaurant serving tajines or couscous is something rare in The Netherlands.
The Restaurant is easy to find and around 12/15 minutes journey from the Centraal station. I went there on a Friday night and the restaurant was full at around 19:00. In fact I ended up using the last free table. If decoration is a must for you - you might not appreciate this venue - as it's very flat.
The menu is very simple and the prices are very correct. You get to choose between Three Couscous , Veget, Maison and Royale, and they are described to you by the waitress, in case you can't figure out what they are :-). I took a royale and it came in good quantity - so this looked like a real couscous to me. The hot sauce wasn't that hot and I was surprised to see some pumpkin and a tomato in the vegetables. The tunisian sidi brahim that I drank with it was more than correct - and in fact I asked for more.
Deserts are not at all related with couscous , but my crème brulée was Delicious.
I liked the place a lot.