Royal Smals has done the essential periodic maintenance of the fishing harbour and yacht harbour in Boulogne-sur-Mer, France. Only the Frédéric Sauvage yacht harbour is behind a sea lock. The fishing harbour is open, with strong tides. Due to the open water, silt is piling up. Periodic dredging is needed to guarantee the necessary depth. We have removed 21,000 m3 of silt and dumped it at a specific ocean site. The marine litter was separated and collected in containers.