The Marché Notre-Dame is Versailles's main market, housed in four covered halls built in the 1840s on the site of the earlier market that served the court. It runs on Tuesdays, Fridays, and Sundays, with outdoor stalls filling the square around the halls on market mornings and the covered halls open daily for permanent stallholders selling cheese, charcuterie, butchery, fish, and wine.
The Sunday market is the largest and most atmospheric: produce from the Île-de-France and nearby Seine-et-Oise farms, cheese from all over France, flowers, olives, and a good deal of prepared food for eating on the go. The town's professional classes shop here alongside tourists, and the quality is high — this is not a market aimed at visitors.
If you are visiting on a non-market day, the permanent covered stalls are still worth a look, and the square around them is lined with good cafés and brasseries for lunch. The whole area around the market — the Place du Marché Notre-Dame and the streets radiating from it — is the civic heart of the town.