This study investigates L2 learners' use of French derivational processes and their strategies as they form agent nouns. It also attempts to find out which of the acquisitional principles (conventionality, semantic transparency, formal simplicity, and productivity) advanced by Clark (1993, 2003) for various L1s acquisition of word formation processes are in accounting for L2 French derivational processes. Twenty-five adult university English-speaking learners in their second semester of French participated in this study. The data was collected by mean of two production tasks: Production task I (based on existing agent nouns), and production task II (based on innovations). The findings reveal that not all the four acquisitional principles account equally well for these L2 learners' use of word formation processes. Only conventionality and productivity principles appear to have a bearing on these learners' use of French derivational processes. Learners tend to use and opt for the productive and conventional derivational process /-eur/ to coin the agent nouns. This study has shed further light on the nature of learners' L2 lexical knowledge and on the order of acquisition of French derivational processes. Possible applications of these findings are discussed. (Contains 2 tables.)