I'm not a huge fan of "commune" (which to me conjures up images of hippies weaving their own tofu!), nor "community" which these days in GB tends to equate to a "subset of the population".

After some research both on Proz and elsewhere when this very term came up in a text of mine recently, the above was what I finally settled on: a "commune" can quite justifiably be translated as "district" in a local govt context, and "Communauté" just means that a few of them are acting in concert, hence "combined.

Note that these tend to be found in rural areas, as no minimum population is required to establish one.