Context : This work is part of a series of studies focusing on the environment and the properties of the X-ray selected active galactic nuclei ( AGN ) population from the XXL survey .
The present survey , given its large area , continuity , extensive multiwavelength coverage , and large-scale structure information , is ideal for this kind of study .
Here , we focus on the XXL-South ( XXL-S ) field .

Aims : Our main aim is to study the environment of the various types of X-ray selected AGN and investigate its possible role in AGN triggering and evolution .

Methods : We studied the large-scale ( > 1 Mpc ) environment up to redshift z = 1 using the nearest neighbour distance method to compare various pairs of AGN types .
We also investigated the small-scale environment ( < 0.4 Mpc ) by calculating the local overdensities of optical galaxies .
In addition , we built a catalogue of AGN concentrations with two or more members using the hierarchical clustering method and we correlated them with the X-ray galaxy clusters detected in the XXL survey .

Results : It is found that radio detected X-ray sources are more obscured than non-radio ones , though not all radio sources are obscured AGN .
We did not find any significant differences in the large-scale clustering between luminous and faint X-ray AGN , or between obscured and unobscured ones , or between radio and non-radio sources .
At local scales ( < 0.4 Mpc ) , AGN typically reside in overdense regions , compared to non-AGN ; however , no differences were found between the various types of AGN .
A majority of AGN concentrations with two or more members are found in the neighbourhood of X-ray galaxy clusters within < 25-45 Mpc .
Our results suggest that X-ray AGN are typically located in supercluster filaments , but they are also found in over- and underdense regions .

Conclusions :