French culture minister Franck Riester could not promise the restoration of the fire-ravaged Notre Dame Cathedral in Paris would be done in five years, arguing that was just an "ambition" fixed by French President Emmanuel Macron.

At a press conference for the six month anniversary of the fire, Riester insisted it was most important to do a quality restoration rather than a quick one.

Part of the reason why they are unable to work quickly is the workers' safety, which the minister said: "stood above all."

"Our obsession is with quality," he said, adding that everyone working on the project was aiming to maintain "a sustained pace" in order to "give back the cathedral back to the people within a reasonable delay."

However, speaking to AFP, the chief architect for the cathedral's restoration Philippe Villeneuve, said the five-year reconstruction period was sustainable if "they keep on working" like they have for the past six months.

Riester said there were "still a few months" of work left to fully secure the cathedral and finish the diagnostic.

He added that the restoration work would still take a few more months before getting to the conservation part of the project.

37 million euros have been used so far for the cathedral's restoration. The rest of the funds collected — 104 million euros in total — will be "given out when needed."

The estimation for the conservation of the historical monument is 85 million euros, he added.

Riester spoke little about the investigation into the fire, saying those were questions for the authorities.

The Paris' prosecutor told Euronews they couldn't comment as the investigation is ongoing.

A massive fire consumed Notre-Dame on the evening of April 15, destroying the roof of the Paris landmark and stunning people in France and the world. Firefighters saved the main bell towers and outer walls from collapse before bringing the blaze under control.