Looking into the waters of French poetry I found this amongst much other interesting stuff:

Rhymes containing only one element, the vowel, not preceded by the consonne d’appui are termed rimes faibles, and, properly speaking, are not rhymes but assonances. Any rhymes containing more than the two minimum elements are termed rimes riches (e.g. puni-muni). Lines can, of course, be richer, with two or more additional elements, as in plier-peuplier, ouvrier-chevrier, etc...

http://www.ex.ac.uk/french/ingrid/versification.htm