FRANCO is an unprecedented effort to review, assess, and attempt to provide key elements for the sustainable management of BCEs in diverse case studies that are representative of the local environment and people. The intended development of pilot ‘proof of concept’ methodologies, established in three types of Blue Carbon Ecosystems (BCEs) found in mainland France, Canada, Spain and French Guiana, will contribute to a better monitoring and understanding of the current transformation processes affecting BCEs, up to the definition of decision support systems upscaled to the Blue Carbon Coast (BCC).