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.