The present study investigates lexical inter- and intralingual influences in the oral production of 14 very advanced learners of French L3. Lexical deviances are divided into two main categories: formal influence and meaning-based influence. The results show that, as predicted with respect to advanced learners, meaning-based influence is the most important category, especially semantic extensions. Furthermore, only the languages in which the learners are highly proficient (Swedish L1, English L2 and French L3) are used in cases of meaning-based influence. By contrast, no use is made of closely related languages (Spanish and Italian). These results indicate that the proficiency factor is decisive for lexical inter- and intralingual influences to occur in advanced learners.