Etang des Moines has some very nice carp in it and you can night fish for them. Lake is located just to the south of Fourmies there is a campsite and hotel very close by.
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.