Carpenters, stonemasons, stained-glass restorers, archaeologists and scientists: 80 workers on the Notre-Dame de Paris restoration site rehearse under the direction of choirmaster Frédéric Pineau to sing together when the cathedral reopens next December. While many of them have never sung before in their lives, all are united by the desire to mark the end of an emotionally-charged five-year project. IMAGES AND SOUNDBITES