Process for activating catalysts for isomerizing aromatic compounds containing eight carbon atoms

A process for activating a catalyst for isomerizing aromatic compounds containing 8 carbon atoms, the catalyst containing at least one group VIII metal and at least one zeolite wherein said zeolite contained in the catalyst is EU-1 zeolite, having an EUO structure, wherein said EU-1 zeolite contains silicon and at least one element T being aluminum, iron, gallium or boron, in proportions such that the global Si/T atomic ratio is about 5 to 100, said EU-1 zeolite also being at least partially in its acid form, said process comprising sulfurizing the catalyst at least once and passivating the catalyst at least once using ammonia.