Etang du Pont Rouge in Quesnoy holds a very good head of Carp and at decent sizes , There is a tackle shop on the lakeside and if you want to fish nights for carp you can but you have to reserve places via the tackle shop. As with all French water rules can change at any time so please check on site or local tackle shop for latest rules.
Please note – When fishing any Public waters in France please have respect for the location and clear up any mess that you have made and do not damage banks / vegetation and no open fires, Catch and release all fish except Trout and Salmon that rules let you take and when fishing for Carp use appropriate fishing tackle with large landing net and unhooking mat. Fish stealing is a big problem from Public waters if you see anybody removing large fish like Carp please take note of the vehicle registration and report to authorities.