Overt subject pronouns in Romance null subject languages are mandatory in order to express contrast, while null subject pronouns are generally prohibited in these contexts. However, most of the literature remains vague of what is meant by contrast. This paper argues that non-focal Romance contrastive pronouns are Contrastive Topics, which trigger topic alternatives and it is implicated that the truth of the alternatives is not known to the speaker (Hara and van Rooij (2007)). This implicature gives rise to an ‘uncertainty contrast’, which can be strengthened into an ‘exhaustive contrast’, in certain circumstances. The pairing between forms and meanings is derived using the mathematical framework of game theory.