This study deals with the acquisition of Functional Categories in the French Determiner Phrase. The development of determiners and prenominal adjectives in three bilingual Swedish–French children is compared with that of four Swedish second language learners of French. It is argued that acquisition is crucially different in these two cases. The bilingual children initially have restrictions on phrase structure, resulting at one stage in a complementary distribution of determiners and adjectives. These results support a structure building view of L1 acquisition. For L2 acquisition of the same structure, there is no evidence for an initially reduced phrase structure. This finding is explained in terms of a transfer effect. A preliminary comparison with the acquisition of finiteness suggests that, whereas there is some correlation over time in the L1B subjects, no such correlation is found in the L2 learners.