In light of the recent Paris Court of Appeals case law, in which the Court has considerably increased its review of the violation of international public policy, it is worth describing the range of tools available to the arbitrator to characterize illicit practices — and in particular, corruption — in order to fulfil the duty of guardian of international public policy that seems to have become part of the arbitrator’s role. The arbitrator will approach corruption all the more efficiently if he accepts to reduce the standard of proof, to broaden the scope of admissible evidence, or even to shift the burden of proof, and to raise sua sponte issues of corruption that are not pleaded by the parties. The active role of the arbitrator in the search for corruption will lead the arbitrator, if necessary, to sanction this practice by declaring void the corrupt agreement or the contract obtained by corruption, while retaining a broad discretionary power in the application of the principle “in pari causa turpitudinis cessat repetitio” in relation to the question of potential restitution between the parties.