Filiform corrosion is an active corrosion cell that moves across the metal surface underneath the coating, leaving a tail filled with corrosion products. Filiform corrosion is a main problem on coated aluminium alloys exposed to a humid atmosphere. The corrosion is generally initiated in defects in the coating and propagates in presence of aggressive ions (chloride, sulphate...), oxygen and sufficient relative humidity. The aim of this investigation is to provide more information on the mechanism of filiform corrosion on coated aluminium alloys using complementary localized techniques: the scanning Kelvin probe (SKP), the Fourier Transformed Infra-Red (FTIR) microspectroscopy and X-ray absorption near-edge structure (XANES) technique. SKP can provide information on the potential distribution during corrosion processes on both bare and coated metals with a spatial resolution of approximately 50 μm. Here, SKP measurements have been performed in order to identify the anodic and cathodic sites on filaments formed on coated aluminium during atmospheric exposure. FTIR microspectroscopy permits the identification of thin surface films of corrosion products both under ex-situ and in-situ conditions. As the spatial resolution is similar to the SKP, this technique has provided information on the composition of corrosion products formed in the head and in the tail of the filaments. The initiation and the propagation of filiform corrosion on coated aluminium alloy were investigated using an experimental set-up for in-situ infrared reflection absorption spectroscopy. It consisted of an in-situ cell, where samples were exposed to controlled humid conditions, and an optical microscope linked with a Fourier Transformed Spectrometer. XANES measurements were performed on coated chromated aluminium alloys in order to study the mechanisms of inhibition of chromate on the filiform corrosion. This was performed using a high resolution beam (e.g. 15-35 μm), making possible the establishment of X-ray maps of Cr(VI) and total chromium over the surface including the filament.