This is a place meant for the locals to do their shopping, hence it is crowded. I visited the place during Ramadan, adding more pressure for the festival shopping.
If you are looking for chinese goods to local stuff, this is the market to visit.
Dont expect comfortable shopping, but you could actually ending up having a good bargain, if...
You will find many things available in Mauritania at marche capitale. But I have to admit it is not my favorite place for shopping. If you just have time for one visit to a market skip this one and go to marche cinquieme.