The commune is an administrative division of France. The rights and obligations of communes are governed by the Code général des collectivités territoriales (CGCT) which replaced the Code des communes (except for personnel matters) with the passage of the law of 21 February 1996 for legislation and decree number 2000-318 of 7 April 2000 for regulations.
[1] (http://www.droit.org/code/index-CGCTERRL.html) Partie législative.
[2] (http://www.droit.org/code/index-CGCTERRM.html) Partie réglementaire.
INSEE codes: INSEE gives numerical indexing codes to various entities in France, notably the communes (they do not coincide with postcodes). The 'complete' code has 8 digits and 3 spaces within, but there is a popular 'simplified' code with 5 digits and no space within :
2 digits (département) and 3 digits (commune) for the 96 départements of France 'métropolitaine'