In French, the members of a subclass of anticausative verbs are optionally marked with the clitic se, traditionally considered to be a reflexive marker. We show that this optionality is not a case of free variation. Rather, the presence or absence of se is influenced by lexical-pragmatic considerations: while by default, both variants are equally acceptable, in the context of a human subject, cooperative speakers strongly prefer the variant that in certain cases avoids and in other cases maintains ambiguity with the semantically reflexive interpretation that arises in parallel with the intended (anticausative) interpretation. Understanding these preferences requires taking into account the agent bias—that is, the tendency to interpret human nouns in subject position as agents whenever possible—and the multifunctionality of se, which is used to form both (nonagentive) anticausative predicates and (agentive) semantically reflexive ones. The preference for the presence vs. absence of se is predicted based on whether the alternative reflexive interpretation is in line with shared assumptions about the event. The interaction between the choice of form by the cooperative language user and individual verb subclasses is an example of what we call lexical-pragmatic effects.