Another possible option. But econeighbourhood could be fine too, depending on who the text is for - the latter sounds very US English to me.

ecodistricts - Found within ecoregions and are characterized as distinctive arrangements of landforms, relief, surficial geologic material, soil, water bodies ...
www.pc.gc.ca/apprendre-learn/prof/sub/eco/itm7/index_e.asp

Community environmental outreach and awareness programme is what it is- but that is a real mouthful. I would keep it in French as they do in Montreal, and use this as a gloss in brackets the first time it occurs.

Often used for this concept

Another suggestion.

Green neighbourhood | Big Green Switch
- [ Traduire cette page ]
4 Feb 2008 ... Plans for 100 "green neighbourhoods" will be laid out on Wednesday by Hilary Benn, environment secretary, as the government faces criticism ...
www.biggreenswitch.co.uk/forum/talkingpoints/Green-neighbou... - 41k -

Features of Sustainable Neighbourhoods | CMHC
- [ Traduire cette page ]
A green neighbourhood that preserves the countryside: Because compact neighbourhoods use land efficiently, natural and rural areas outside your community ...
www.cmhc-schl.gc.ca/en/co/buho/sune/sune_001.cfm - 52k -

CRII: Wehringhausen - a green neighbourhood (D)
- [ Traduire cette page ]
flowery impressions The aim of the project is as a green neighbourhood and to motivate the inhabitants to activly work on the creation of a green ...
www.city-identity-image.com/index.php?id=129 - 18k -

I've encountered this most frequently (exclusively?) in reference to Freiburg im Breisgau just the other side of the border (lovely town, fond memories ...) but other examples come up, even when Googling "eco-community + Freiburg":

My next-door neighbor Olga and I shelved our original plan yesterday to go to a Sommerfest in Vauban, the ECO-COMMUNITY in Freiburg. ...
www.young-germany.de/yg/blog/blog-singleview/article/ba1f4a...

We kick off with Freiburg’s ECO-COMMUNITY, including the new Sonnenschiff development that could teach the UK housebuilding sector a thing or two … ...
www.propertyweek.com/story.asp?sectioncode=482&storycode=30...

is the United Kingdom’s largest carbon-neutral ECO-COMMUNITY. .... The German city of Freiburg is known as Germany's solar and environmental capital. ...
www.myplanetintl.com/grn-development-02-10-2008.php

out to Findhorn, an ECO-COMMUNITY 45 minutes south of In- verness, for a short visit, ... Freiburg to meet a maximum heating load of 65 kWh/m ...
www.regniertravelingfellowship.org/documents/FellowshipMont...

site in the south of Freiburg, Germany. The area is home to 500 residents ...... on to see the proposed ECO-COMMUNITY at Bordon / Whitehill in Hampshire. ...
www.gos.gov.uk/497648/docs/237105/NewsletteIssue20




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Note added at 8 hrs (2009-04-24 06:33:53 GMT)
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Un article de Wikipédia, l'encyclopédie libre. Aller à : Navigation, rechercher. Le quartier VAUBAN est un ECOQUARTIER de la ville de FRIBOURG-EN-BRISGAU, ...
fr.wikipedia.org/wiki/Quartier_Vauban_de_Fribourg-en-Brisgau

Le quartier VAUBAN, à 2,5 km au sud du centre ville est l’exemple d’un ECOQUARTIER d’une diversité architecturale. Petits immeubles en forme ...
blog.bmykey.com/immobilier/international/vauban-ecoquartier-de-la-ville-de-fribourg-en-brisgau/2007/150/

Dans une atmosphère conviviale, sa présentation en image de L'ECOQUARTIER VAUBAN de FRIBOURG fut riche d'enseignements. Parmi les idées fortes à retenir : ...
www.bihorelavecvous.com/2008/01/20/ecoquartier-vauban-de-fr...


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Note added at 9 hrs (2009-04-24 06:38:27 GMT)
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In Canada too :

an example of a low carbon ECO- COMMUNITY, is in Wallington, SOUTH LONDON. ...
www2.canada.com/MONTREALGAZETTE/features/greenlife/story.html?id=80e3b68b-f470-4c62-8c96-4b51f2605b12

15 Jun 2007 ... Le Vistal Condo, Nun’s Island, Montreal ... gym, indoor pool and outdoor pool) ECO-COMMUNITY (LEED, Green Loan) and the developer proment. ...
levistalcondo.wordpress.com/

26 Nov 2006 ... CHEK NEWS, CHBC NEWS, CHCA NEWS, CHCH NEWS, CJNT Montreal ... too, as plans to build a model ECO-COMMUNITY at the FORMER CANADIAN FORCES ...
www.CANADA.com/ottawacitizen/features/story.html?id=5dc571e...

The Gazette (Montreal), DOSE, Canwest Community Publishing, Nanaimo Daily News ... Next comes an ECO-COMMUNITY NORTH OF THE QUEENSWAY in deep suburbia ...
www.OTTAWAcitizen.com/columnists/Green inspiration/1289745/...

The selected site in Montreal is bordered by Guy, Sainte-Catherine, Peel streets .... is a carbon-neutral ECO-COMMUNITY that incorporates mixed-use tenancy. ...
www.leap.umontreal.CA/en/projets/logement2007/goals2007.htm

Ecodistrict

I'd go for this because (I think?) district is closer to the "official" (i.e. town planner's) view, and I gather from the context that this is more of a "top-down" planning document than a "bottom-up" neighbourhood type scheme.

Also, I'd go for "eco" rather than "green", as that's becoming very tired and worn at the edges, and its meaning is becoming increasingly fuzzy…

I see that you limited your request for responses to those in the env. field; you might try expanding it to architects and town planners…. just a thought.

Geoffrey Bird