A catalyst which comprises an amorphous support based on alumina, a C1-C4 dialkyl succinate, citric acid and optionally acetic acid, phosphorus and a hydrodehydrogenating function comprising at least one element from group VIII and at least one element from group VIB; the most intense bands comprised in the Raman spectrum of the catalyst are characteristic of Keggin heteropolyanions (974 and/or 990 cm−1), C1-C4 dialkyl succinate and citric acid (in particular 785 and 956 cm−1). Also a process for preparing said catalyst in which a catalytic precursor in the dried, calcined or regenerated state containing the elements of the hydrodehydrogenating function, and optionally phosphorus, is impregnated with an impregnation solution comprising at least one C1-C4 dialkyl succinate, citric acid and optionally at least one compound of phosphorus and optionally acetic acid, and is then dried. Further, the use of said catalyst in any hydrotreatment process.