Generally it refers to "community project", something done for the "collectivité", so might encompass community halls, municipal baths, public libraries, etc. It is POSSIBLE that there are constraints on public planning that do not apply to private construction projects (to better protect public money from misspending).

Specifically it could also apply to large, dense housing projects, be they public or private sector, given that high-rise construction places more constraints on the foundations than your average bungalow home.

--------------------------------------------------
Note added at 5 mins (2004-12-06 13:59:46 GMT)
--------------------------------------------------

Of course it might cover both, if we are looking at publically funded high-rise housing.