Perhaps the only Mauritanian restaurant in Montreal, La Khaima is one of the best options if you are looking for a place to eat in the Mile End area. The decor is warm and cozy, with cloth covering the ceiling and giving a tent-like atmosphere. The owner, Attigh acts as server, cook, host and entertainer. He is a really interesting character and was the subject of an award winning documentary (http://vimeo.com/11617345).
The menu varies, but everything I have tried there has so far been excellent. The cuisine is very similar to Moroccan cuisine and the menu usually includes one tajine, and one vegetarian option. You can ask for a sample platter containing the various menu items of the day.
The mint tea at the end is one of the highlights of the meal. It is sweet and intensely fragrant, and as a bonus, Attigh turns the process of oxygenating the hot brew into a fun show to watch.
La Khaima is a real treat and is highly recommended.