The Champ de Mars sits in a natural amphitheatre south of the city centre, ringed by mountains and overlooked by the citadel of Fort Adelaide. Racing happens on Saturdays from late March or April to late November, and the meetings are the closest Mauritius gets to a national festival — crowds of tens of thousands, formal hats, betting tickets, families with picnics.
If you're in town on a race Saturday, go. Entry to the public stands is cheap (Rs 30–50), the atmosphere is unlike anything else on the island, and even without betting you can spend a happy afternoon people-watching. Off-season the field is a public park.