Construction teams brought in a huge crane and a delivery of planks of wood to the site Wednesday morning.
Firefighters are still examining damage and shoring up the structure after the fire collapsed the spire and destroyed the roof.
French President Emmanuel Macron ratcheted up the pressure by setting a five-year deadline to restore the 12th-century landmark. Macron is holding a special Cabinet meeting Wednesday dedicated to the Notre Dame disaster, which investigators believe was an accident possibly linked to renovation work.