demandeur

Noun

 * 1)  The party, generally a state, that seeks to forestall or respond to noncompliance with or violation of an international law or treaty.

Etymology
From.

Noun

 * 1) asker or requester (one who asks or requests something)
 * 2) seeker

Noun

 * 1)  complainant, plaintiff (one who  brings a lawsuit against another)