A conurbation community is a public establishment for inter-communal cooperation that brings together several municipalities forming, on the date of its creation, a contiguous and unenclosed area with a population of more than 50,000, around one or more central municipalities with a population of more than 15,000. The population threshold of 15,000 does not apply when the agglomeration community includes the capital of the department or the largest municipality in the department, or when the most populous municipality is the central municipality of an urban unit with more than 15,000 inhabitants. The population threshold of 50,000 is reduced to 30,000 when the agglomeration community includes the departmental capital. The demographic threshold of 50,000 inhabitants may also be assessed by taking into account the population as defined in article L. 2334-2, on the double condition that the latter exceeds this threshold by at least 20% and exceeds the total population by more than 50%. The perimeter of an agglomeration community may not include a municipality that is already a member of another public inter-municipal cooperation establishment subject to the provisions of article 1609 nonies C of the General Tax Code on 1st January 1999, if the municipal council of the municipality concerned has voted against the decree drawing up the list of municipalities or if more than a quarter of the municipal councils of the municipalities that are members of the existing establishment oppose the withdrawal of the said municipality. These municipalities join together to form an area of solidarity, with a view to drawing up and managing a joint urban development and land-use plan for their territory. Where the conurbation community includes one or more priority neighbourhoods for urban policy, this joint project includes a section on social and urban cohesion, making it possible to define the guidelines for the conurbation community in terms of urban policy and strengthening solidarity between its member municipalities. It determines the ways in which the competencies of the conurbation community contribute to the objectives of social and territorial cohesion.
On an experimental basis and for a maximum period of three years from the promulgation of Act no. 2013-403 of 17 May 2013 on the election of departmental councillors, municipal councillors and community councillors, and amending the electoral timetable, the State may authorise the formation of an agglomeration community, within the meaning of the first paragraph, when it forms a whole of at least 30,000 inhabitants and includes the most populous commune in the department.
On an experimental basis and for a maximum period of eighteen months from the promulgation of Law no. 2014-58 of 27 January 2014 on the modernisation of territorial public action and the affirmation of metropolises, the State may authorise the formation of an agglomeration community, within the meaning of the first paragraph, when it forms a group of at least 25,000 inhabitants around a central municipality of more than 15,000 inhabitants and the majority of the member municipalities, including the central municipality, are coastal municipalities within the meaning of article L. 321-2 of the Environment Code.