Recent decade has been prominent in investigating third language acquisition (L3). This study presents an Optimality theoretic account of French wh-question by learners whose first and second language are Persian and English respectively. Additionally, it investigates transfer at the initial stage based on the three dominant transfer hypotheses namely, L1 transfer hypothesis, L2 status factor, Cumulative Enhancement Model (CEM) in the domain of L3 acquisition. First, in French and Persian wh- question structure, the wh-word move to pre subject position (Spec-CP & Spec-FOCP) but the interrogative verb do not raise to C. This is the indicator of L1 Factor hypothesis. Second, in French and English the wh-word follows by an interrogative verb in French or by subject-auxiliary inversion in English so in these languages the wh-word occupies the Spec-CP and the verb occupies the C position. This is an evidence for L2 status factor. Third, in English and Persian the wh-word remains in original position for echo questions, this feature triggers this parallel structure in French; this confirms Cumulative Enhancement Model hypothesis. Two groups of Persian native speakers with different English proficiency levels (the lower-intermediate & advanced) that were at the initial stage of acquiring L3 French were asked to complete two test namely, grammar judgment task and translation test. The results showed that the main source of transfer was L1 transfer hypothesis and partially CEM. Regarding OT, although the advanced learners transferred their L2 knowledge in the L3 acquisition in GJT, there was not any significant difference between L1 transfer and L2 transfer context. Therefore, the following constraint hierarchies were obtained for TT and GJT respectively, Q-Scope>> Lex-V>Stay>>Q-Mark and Stay>>Lex-V>>Q-Mark>>Q-Scope. In fact, these ranking, particularly the former one, advocated the L1 transfer hypothesis.