Markets always have fresh produce / meat /cheese / bread. The bigger ones have furniture / garden tools / livestock.
Do not expect prices to be cheaper than the supermarket ~ the French are willing to pay for fresh produce.
Get there early ~ you will note that by 11.30 many stalls are already packing up for lunch and by 12.30 it is all over.
Unlike UK and many European markets ~ it is not normal to 'sell-off' left over produce at the close.