Now things have got heated between Jean-Louis Georgelin, the French President's special representative for the reconstruction of the cathedral, and chief architect Philippe Villeneuve.
"I have asked to him (Villeneuve) a few times... to shut his mouth so that we can move forward wisely to serenely make the best choices for Notre Dame," Georgelin said during a meeting Wednesday.
Villeneuve has previously said the Notre Dame spire should be rebuilt as it was before the devastating fire -- a view with which Georgelin plainly doesn't agree.
In April, French Prime Minister Édouard Philippe announced an international architects' competition to rebuild the fallen spire of the cathedral.
Debate has centered on whether to rebuild the spire identically or to redesign it.
Philippe himself has expressed interest in a more modern redesign, while Paris Mayor Anne Hidalgo said she favors an identical restoration.
There are also differing opinions over the timeframe of the restoration project.
With the Summer Olympics due to be held in Paris in 2024, French President Emmanuel Macron plans to have the structure rebuilt in five years.
In April Macron said that when it is rebuilt, it should be "even more beautiful."
But some have criticized the shorttime line as a political ploy.
Restoration expert Frédéric Létoffé said he thinks it could take longer, at around "10 to 15 years."