Abstract
This chapter discusses the gaps in some of the combinations of the preverbal clitics in French. These gaps present a powerful tool for evaluating the foundational hypothesis governing the architecture of the language, particularly the morphophonology-free syntax of the language. In the French clitic cluster, the gaps are divided into two categories: the syntactic groups and non-syntactic groups. The syntactic groups invoke syntactic information. The non-syntactic groups meanwhile are comprised of gaps invisible to syntax and dependent on morphophonological information and mechanisms. Also discussed in the chapter is the Person Case Constraint, a syntactic principle that forms the foundation against which other gaps may be measured. Some anomalous combinations are also discussed in the chapter. These combinations betray the workings of the extra-syntactic system which manipulates the morphological features and which imposes constraints on such combinations.