This study explores the development of an environmentally friendly binder by integrating locally sourced port sediment from Dunkirk Port with waste paper fly ash (WPFA). The aim is to innovate construction materials with a reduced carbon footprint, without prioritizing high mechanical performance. The sediment was processed to achieve two levels of fineness, namely 10 microns and 2 microns, to increase its reactive potential. The formulation of the eco-binder involved a mixture of 75% port sediment and 25% WPFA. Findings indicate that optimal compressive strengths, reaching 14.8 MPa, were obtained in highly humid environments (> 95% R H ) at a temperature of 50 °C. It was observed that finer sediment particle size (2 microns) contributed to enhanced mechanical properties. Nonetheless, the sediment's pozzolanic activity is somewhat restricted at ambient temperatures, necessitating specific conditions for effective reactions. Environmental safety assessments confirm that the produced eco-binder meets the criteria set forth in the SETRA guidelines for sustainable use in construction. The leaching and release potential of WPFA after the development of the eco-binder was meticulously assessed using the four-phase sequential extraction method recommended by the Reference Bureau of the European Communities Commission (BCR). A marked change was observed in the speciation of trace metal elements, with a predominant transition from the soluble fraction to the carbonate fraction, attributed to the carbonation process. In conclusion, the marine sediment investigated shows promise as a sustainable construction material, provided that controlled temperature and humidity conditions are maintained to attain adequate mechanical strengths.