qui for qui est-ce qui

31. qui d'écharpe changeants, in the first place we must remark that changeant should not grammatically hâve an s. We bave given it with the s, because it is found so spelt in the best texts, and there is no doubt that La Fontaine wrote it so for the sake of the ocular rime with gens. In doing so La Fontaine only followed the rule of the old French language, in which the présent participle was always declined.

qui eVécharpe changeants, litterally means 'changing scarf that is 'changing colours', 'turn coats'.