This article explores the widely documented difficulty with object clitics in the acquisition of French. The study investigates the effects of L1 transfer and processing limitations on the production and comprehension of object clitics in child L2 learners of French with different L1 backgrounds (Chinese, Spanish). The Spanish-speaking learners performed better than Chinese-speaking learners on clitic-related tasks, indicating a facilitative effect of transfer when the L1 also has object clitics. Yet no evidence was found for (negative) transfer of null objects from Chinese to French, as learners consistently rejected interpretations requiring referential null objects on a receptive task. The frequency of Chinese-speaking learners' object omissions in production was negatively correlated with an independent measure of working memory (backward digit span), consistent with the hypothesis that object clitic omission is affected by processing limitations. These findings are discussed within a psycholinguistic model of syntactic encoding during language production.