With a binding price floor (set above equilibrium), the market price stays at the floor, even if demand falls, so the price does not decrease.

However, when demand decreases, the quantity that buyers are willing to purchase at that floor price becomes even smaller, so the amount actually sold/produced falls and the surplus grows.

So:

  • Market price: remains at the (unchanged) price floor.
  • Quantity produced/sold: decreases, and excess supply (surplus) becomes larger.