The invention relates to a structure, comprising a substrate supporting a
layer with a photocatalytic and anti-soiling property on at least part of
the surface thereof, said layer being based on titanium dioxide
(TiO.sub.2) which is at least partially crystallized in the anatase form
thereof. Said structure is characterised in comprising a sublayer (SC)
directly under at least one TiO.sub.2 layer, said sublayer having a
crystallographic structure which provides assistance to crystallization
by heteroepitaxial growth in the anatase form of the TiO.sub.2-based
upper layer, the photocatalytic property being obtained without any
heating step.