May is a great time to visit Paris. Weather should be nice and there will be a lot happening. The African and Oceanic art wing of the Louvre is cool, and definitely worth checking out.
There's plenty of African music, dance and art in Paris; tons of artists immigrate there. I don't know that there's a single club or hotspot that specializes in African music (there's a place called Taxi Mandingue in Brussels), though certain neighborhoods are predominantly African - Belleville, Ménilmontant, and Barbès. The flea market at Porte de Clignancourt feels like an African market.
I once saw Adama Drame and Foliba at a place called Le Trabendo, but there are plenty of spots like that throughout the city. I would check out
http://www.pariscope.fr before your trip, or write this guy:
http://bennloxo.com/.