Cyrano de Bergerac could easily have been melodramatic if it were not for the fine balance of the play: the actions and settings are well matched; the interest of the audience is held by color and excitement until the characters develop; and the costumes suit the setting, the mood, and the action.
Act I, in the theater, is lively and colorful. Act II is also in a public place, and many people appear on stage. The third act, on a darkened street, is very quiet. Cyrano's good deed — holding De Guiche's attention while Roxane and Christian are married — is performed in near darkness. Act IV again has the cadets on stage. The battlefield setting is not gay and cheerful, as are the first two settings, but it is still colorful. Act V is in the quiet courtyard of the convent. If Acts III and V were contiguous, the audience might well grow bored, but the color of Act IV provides contrast if not actual relief.
As interest in the characters develops, the settings have less intrinsic interest, and do not distract. The darkness of Act III is in keeping with Cyrano's dashed hopes and is necessary for the deception as well. And it is worth noting that, in Act V, most of the costumes — specifically, Roxane's mourning dress and the nuns' habits — are black, foreshadowing, and complementing the idea of (Cyrano's) death.