Paris isn't a cruise port, but is served by the port of Le Havre. In total, the port of Le Havre serves as the port of departure for only one annual sailings from both Cunard and MSC to Europe.
On average Paris is fairly expensive compared to other ports. The chart below shows the monthly average cost per day for cruises from Paris (Cruises only depart from Paris between July and October). Sailings scheduled from Paris during the the peak season of summer are significantly more expensive than the the low season of fall.