Language interference is one of the factors that affect language learning by many learners of second and third languages. In Zambia, the impact of language interference on the learners of French requires closer attention. Our literature review shows that few studies have looked at the impact of interference from Zambian languages on the learners of French. This study is an investigation into syntactic errors that are committed by high school pupils learning French in Lusaka Province, the capital city of Zambia. The participants in this study are pupils whose mother tongue is Bemba with English as their second language, learning French as their third language or second foreign language. The study highlights a number of errors that are committed due to transfer of L1 (Bemba) and L2 (English) syntactic structures in the production of L3 (French) syntactic structures. This study has revealed four categories of syntactic errors namely; agreement errors, word order, coordination errors and sentence errors. English language was found the more interfering language rather than Bemba. However, no coordination errors were recorded as resulting from the interference from English. The study also revealed that the predominant source of errors is interlingual rather than intralingual.