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Polarisation is a decisive method to study the inner region of activegalactic nuclei (AGNs) since it is not affected by contrast issues similarly tohow classical imaging is. When coupled to high angular resolution (HAR),polarisation can help to disentangle the location of the various polarisingmechanisms and then give an insight on the physics taking place on the core ofAGNs. We obtained a new data set of HAR polarimetric images of the archetypalSeyfert 2 nucleus of NGC 1068 observed with SPHERE/VLT and we aim in this paperat presenting the polarisation maps and at spatially separating the location ofthe polarising mechanisms, thus deriving constraints on the organisation of thedust material in the inner region of this AGN. We then compared thesemeasurements to radiative transfer simulations of scattering and dichroicabsorption processes, using the Monte-Carlo code MontAGN. We establish adetailed table of the relative importance of the polarising mechanism as afunction of the aperture and of the wavelength. We are able to separate thedominant polarising mechanisms in the three regions of the ionisation cone, theextended envelop of the torus and the very central bright source of the AGN.Thus, we estimate the contribution of the different polarisation mechanisms tothe observed polarisation flux in these regions. Dichroic absorption isestimated to be responsible for about 99 % of the polarised flux coming fromthe photo-centre. However, this contribution would be restricted to thislocation only, double scattering process being the most important contributorto polarisation in the equatorial plane of the AGN and single scattering beingdominant in the polar outflow bi-cone.

High angular resolution polarimetric imaging of the nucleus of NGC 1068: Disentangling the polarising mechanisms