Uqbah bin Amir (may Allah be pleased with him) says that I heard the Messenger of Allah (peace and blessings be upon him) saying: "The one who (unjustly) takes taxes will never enter Paradise."
By "tax" (maks) is meant the reduction by which the collector diminishes the rights of the poor and does not give them their full rights. (When he does this) he will be a "tax-taker", and one should fear the sin upon him and its consequence. And Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13175