The efficiency and the selectivity of a model platinum based catalyst supported on a modified ceria–zirconia oxide was evaluated in the NO x storage-reduction (NSR) process at four catalytic scales: powder, (0.5″×1.5″) flow-through monolith (FTM) system, small size (1″×2″) and full size (5.66″×10″) catalysed Diesel Particulate Filter (DPF).The washcoating of the active phase over FTM affects both the NO x storage properties and the NO x reduction step. The reduction step efficiency is especially decreased at low temperatures. It is associated with an incomplete regeneration of the storage sites and with a strong NO x desorption peak during the rich pulses of the NSR process for the FTM supported system. The NO x reduction selectivity is also strongly affected by the upscale, with an important N 2 O selectivity detected over FTM. The recorded NO x profiles during NSR cycles indicate a probable diffusion limitation. However, same trends were observed for both powder and FTM systems concerning the effect of the reductant mixture, for both NSR efficiency and N-compounds selectivity.After incorporation of the active phase in the porosity of the DPF, a sharp drop in NO x storage properties and subsequently in NSR efficiency are observed. Supplementary tests suggest that the diffusion from the platinum oxidizing sites to the storage sites is again very affected by the upscale. Finally, the engine bench tests confirm the low DeNO x activity of the DPF system.