The drafting of a non-transparent clause can be sanctioned either by attributing to it the unfavorable meaning to the predisposing party or through its ineffectiveness, with consequent applicability to the disputed case of the dispositive regulation and without prejudice, in both cases, to the right to compensation for further damage. The duty of the "clare loqui" is not only an interpretative instrument substantially linked to the "tradi-tional" rule of “interpretatio contra proferentem”, but also an instrument of protection of the weak contracting party (not only the consumer) but also to regulate the market.
Battelli, E. (2021). El principio del «clare loqui» y la tutela del contratante débil. REVISTA BRASILEIRA DE DIREITO CIVIL(1), 147-164.