This paper is intended to be the first part of a study contrasting the subjunctive of French with that of English and comparing it in both languages with the syntactic devices that can replace it. It examines the syntactic constraints on the use of subjunctive forms in French, the semantic contrast between indicative and subjunctive forms, and the semantic changes caused by the replacement of the subjunctive. Three types of French predicates induce their complement verbs to take the subjunctive under certain conditions. In addition, relative clauses can exhibit a meaningful indicative-subjunctive distinction which is not lexically conditioned. The [plus/minus referential] contrast expressed by this opposition is quite similar to the "fact" or "affirmation" vs. "hypothesis" distinction that characterizes the complements of predicates allowing an indicative-subjunctive contrast. One can therefore conclude that the indicative-subjunctive meaning difference in complement clauses is generally [plus/minus real]. The last two sections discuss the ongoing loss of meaning in the French subjunctive and its replacement by other forms. Some predictions are made about the future course of the decline of the subjunctive in French. Certain meaning neutralizations and changes entailed in the replacement of the subjunctive by other syntactic devices are discussed here. (Author)