Anouilh uses the chorus in much the wame way as Sophocles did - though with some twists. As in the classical play, the Chorus comments on the action, gives some background information, and sets the tone of the tragedy. Also, like the classical model, he rarely interacts with the other characters, but gives his observations in soliloquy.
Anouilh's Chorus remains generally neutral, whereas in Greek tragedy, the chorus would frequently take sides in the drama, give advice, and react negatively or positively to the action going on around them. Anouilh's chorus does so only a very little.
Significanly, the Chorus's two long speeches at the beginning include a commentary on the nature of tragedy, and he predicts the fates of the characters. Such was not so in the classical. This has the effect of emphasizing that this is an old tale retold, not something invented for propaganda purposes. It also prepares the audience for the play that is to come; emhasizing that everyone's fate has been dicided, and yet strongly implying that "fate" is a direct result of character.