Public transport has become a major issue in the area of spatial planning and sustainable development. In France, since 1982, public transport has come under local authority management, and, in most cases, operating is delegated to transport operators, which are often members of major transport groups. This way of organising public services now poses complex legal and institutional problems. Local authorities now find themselves having to deal with difficult issues, requiring multi-disciplinary expertise (technical, economic, financial, legal and institutional). The bid to ensure coherence between local public transport policies, and to integrate public transport systems within a general transportation plan, adapting these systems to developments in mobility and in the specific cities and regions concerned, ensuring investment in networks and financing for operating, assessing public transport projects and policies, etc. - now more than ever before, dealing with these issues calls for available knowledge and skills to be shared and simple tools to be developed in response to the needs of contracting authorities.