Maps of the 26 deg² of the N1 field, from left to right: 217, 353, 545 and 857 GHz. From top to bottom: raw HFI maps; CMB- and ERCSC source-cleaned maps; residual maps (CMB-, sources-, and cirrus-cleaned); residual maps smoothed at 10′ to highlight the CIB anisotropies. The joint structures clearly visible (bottom row) correspond to the anisotropies of CIB. Residual point sources are also visible. They have fluxes lower than the fluxes of the ERCSC removed sources. They have no impact on our analysis.