Abstract
Defined as generalized practices with a legal force, usages play a significant role in arbitration. This role is due in particular to the limited legal provisions applicable for this alternative mode of resolution of disputes. One may observe this impact on the substance of the litigation. Usages are indeed rules of law as they produce legal effects. Even though statutes particularly recognize this role with respect to international arbitration, we suggest not to limit the impact of usages to this international context; this point of view may be explained in particular by criticisms to the dualism between domestic and international arbitration.
One may also note the role of usages on the proceedings. This role produces various consequences on the arbitral procedure in particular with respect to the definition of the powers of the Chairman of the arbitral tribunal as well as in connection with the professional and social activities surrounding arbitration.