Paris is not actually a cruise port, but is served by the port of Le Havre. In total, Le Havre serves as the port of embarkation for twenty cruises per year from MSC to Europe.
Overall Paris is extremely inexpensive compared to other ports. Look at the illustration below for the monthly average cost per day (Cruises only depart from Paris between February and December). Sailings departing from Paris during the the peak season of spring are considerably more expensive than the the low season of fall.