Some of the conventions a composer had to follow when writing for the Paris Opéra have long been well known: a four- or five-act design, grand emotions (i.e., a focus on issues that concern a large segment of society rather than isolated individuals), ballets, extended choral sections, musical forms that complied with French expectations (such as ternary aria forms), and certain dramatic requirements. But when it comes to defining French melody in the broadest sense, including consideration of rhythmic and harmonic characteristics, relationship to prosody and accompaniment, and principles of melodic development, opinions have been vague and often contradictory. One nineteenth-century critic for the Gazzetta musicale di Milano, for example, questioned whether the melodic style even at the Opéra could truly pass as French. In reaction to a review in a Berlin paper that detected French influences in Verdi's Rigoletto, the critic responded: