Reduplicated forms in French are always consonant-initial disyllables with an initial light syllable. When the base is a light syllable, the final syllable of the reduplicated word is also light. When the base is a heavy syllable, the final syllable of the reduplicated word is also heavy. If the simplex is polysyllabic, reduplication involves truncation in order to achieve a monosyllabic base (Scullen 2002: 178).
Diachrony
Reduplication in French does not descend from Latin. It has its origin in child language.
Reduplications are documented since the middle age, but the documented cases increase with the 19th century; cf. also Portuguese (Rainer 1998).
Productivity
Reduplication is a productive process in French. The most productive process of reduplication in current spoken French is with inputs consisiting of a single heavy syllable (cf. Scullen 2002).
Repetitive Operations
onomatopoetics, e.g. glou-glou, toc-toc; emphasis/intensification, e.g. très très folle "very very crazy"
Recursive Operations
e.g. "très très chic"
Stylistic Information
Reduplication is typical for colloquial speech (argot) and for child directed speech.