When I received the VHS copiy of the 1988 contest in the early 1990's and got to hear the French entry again, my opinion changed. I also learned that Gérard Lenorman was an established star in his home country and his trembly voice was his trademark. His performance was also far from insecure. He controlled the stage and it felt like he was not singing to the camera but personally to me sitting by the tv.
The song itself, written by the crooner himself, is nothing special, but a well crafted love song made to honor the French ballad traditions, not much different from French eurovision ballads from the 1960's. The orchestral arrangement by the Eurovision veteran Guy Matteoni emballishes the song which on stage is bigger and more pompous than the rather sparsely arranged recorded version.
The studio version of the song is completely another story. On his album Heureux qui communiquent and on single the song is over four minutes long. To make the song fit the three minutes maximum length the track was edited to leave out every other phrase rather than to edit out a verse or a refrain. So if you have only heard the Eurovision version of the song (available on the 1988 Eurovision compilation album), be prepared to surprises when you listen to the album version of the song. In either way Chanteur de charme is one of the better songs of the 1988 contest.
My points 4/5.