  We perform a detailed analysis of the network constituted by the citations in
a legal code, we search for hidden structures and properties. The graph
associated to the Environmental code has a small-world structure and it is
partitioned in several hidden communities of articles that only partially
coincide with the organization of the code as given by its table of content.
Several articles are also connected with a low number of articles but are
intermediate between large communities. The structure of the Environmental Code
is contrasting with the reference network of all the French Legal Codes that
presents a rich-club of ten codes very central to the whole French legal
system, but no small-world property. This comparison shows that the structural
properties of the reference network associated to a legal system strongly
depends on the scale and granularity of the analysis, as is the case for many
complex systems
