Apparently they are already recruiting stonemasons from all over Europe from other historic churches. The head of the reconstruction effort is, AFAIK the firmer head of of Cologne's cathedral stonemasonry / maintenance crew. And the first woman to reach such a position. She got recalled from retirement

Well, now that will definitely lead to shortage of the experts elsewhere in Europe. But I'm not too worried about Notre Dame. Could also proof to be a field day for archeologists from all over the world.