I can second what Mme Tortue said. I did just come back from Mauritius and went with Air Mauritius, and it was quite good. What I did like best is the inflight-entertainment, as they have a small videoscreen in the back of each seat, and you can choose between different movie-channels (even in economy-class!).
I also liked the food on Air Mauritius (spicy, creole food).
British Airways isn't bad as well, though you probably pay a little more.
Avoid Air France, when I was in Mauritius I talked to a girl who did go with Air France, because she got her tickets there cheap (her mother worked for AF), and even she said she wouldn't choose it, if it wasn't for the cheap ticket. She also mentioned that if the AF-flight has stopover in Paris, you run the risk of being stranded at the airport, if the airport-staff decides to go on strike, which is quite common in France.
So, I'd take Air Mauritius or British Airways.