Across the world, every year, several millions of tons of sediments are dredged in harbours. These sediments, which are sometimes polluted, represent an interesting granular resource for the civil engineering. For this study, fine sediments are chosen because of the difficulties to evacuate them after dredging, in comparison to sands, induced by their high water content, the presence of organic matters, their mechanical behaviour and, in some cases, the presence of pollutants. The paper shows the study carried out with fine sediments from harbours of the north of France. The authors propose recommendations to optimize the re-use of these sediments in considering technical, environmental and economical criteria. A re-use process has been studied in laboratory and tested on field site.