Code-switching (CS) between French and Arabic is common across North Africa and in parts of the Middle East. Many researchers have examined this phenomenon in Tunisia (Belazi 1991, Lawson & Sachdev 2000, Belazi et. al 1994) and Morocco (Abbassi 1977, Bentahila 1983, Bentahila & Davies 1983, Lahlou 1991, Redouane 2005.) Corpus and elicited data from these two countries has helped form the basis of proposed universal constraints on code-switching, specifically the Functional Head Constraint (FHC) (Belazi et al 1994) and the Complement Adjunct Distinction (CAD) (Mahootian and Santorini 1996). However, CS between French and Moroccan and Tunsian dialects has not been directly investigated within a single study. This study is a step in filling that gap. Using a web-based survey, the present study examines native dialect speakers' ratings of authenticity of sentences that contain both French and Arabic with a switch occurring in the Determiner Phrase (DP). The syntactic structure of the DP in the dialects examined is the same, (DP = D (D) N (A)). This is similar to the DP in French (DP = D (A) N (A)) with a few key differences that make it possible to test the FHC and CAD within the DP alone. An example of one of the eight possible switch types, between an Arabic Demonstrative Determiner and a French Definite Determiner, is seen here between Moroccan Arabic and French: Men dima had l'homme n'aime pas les chiens. (Since always this the man doesn't like dogs.) A mixed-model ANOVA performed on the participants' ratings reveals main effects for dialect, sex and switch type. Significant interactions also exist, including an interaction between switch type, sex and dialect. While further research is needed, the results indicate that syntactic constraints may not be the only way to understand the practice of CS. Instead, a typological approach, as suggested by Muysken (2000), may lead to a more complete understanding of why and how communities use multiple languages.