Not quite sure how we jumped from OP's plan to visit 3 cities in France to Belgium sidetrips but regardless I would counsel them that less is more and would try and simplify plans where possible.
PTravel has asked but we don't have an answer yet whether this is OP's first visit to France or any of the planned destinations as that would change things for me. If it is a first visit seeing more of a Paris should be a priority, at least IMHO.