Put sauce in a 3-cup container, cheeses in 2 1-quart bags, pepperoni in 1-quart bag; wrap bread in heavy foil.
Freeze them together.
To prepare for serving, thaw French bread, sauce, grated cheeses and pepperoni.
Slice loaf of French bread in half lengthwise.
Layer sauce, Parmesan cheese, pepperoni and mozzarella cheese on each half.
Set oven to broil and/or 550°.
Place bread on baking sheet, and put in the oven.
Broil until mozzarella is melted.