Notre-Dame Cathedral in Paris was unable to hold Christmas Eve Mass for the first time in more than 200 years - after a fire ravaged its structure in April.

With heavy hearts, French Catholics instead gathered at the nearby church of Saint-Germain l'Auxerrois, a few hundred metres away, for a service celebrated by the cathedral's rector Patrick Chauvet.

"It isn't the same feeling but it's still a Christmas Mass," said 16-year-old Juliette, who had made the 700-kilometre trip from Aix with her family. "There will be a thought for Notre-Dame tonight, that's for sure."

"We have been crying since April 15, and today even more," said Danielle, a Parisian, who attended last year's mass at the Paris landmark. However, she was lifted by the choir of Notre-Dame, who performed at the mass.

Meanwhile, workers continue to repair and rebuild the cherished cathedral.

Notre-Dame, part of a UNESCO world heritage site on the banks of the River Seine lost its gothic spire, roof and many precious artefacts in the fire, which was watched by huge crowds. 

The building had remained open for Christmas through two centuries of often tumultuous history - including the Nazi occupation in World War II - being forced to close only during the anti-Catholic revolutionary period in the late 18th and early 19th centuries.

President Emmanuel Macron has set a timetable of five years to completely repair the eight-centuries-old structure, which remains shrouded in scaffolding with a vast crane looming over it.

Paris prosecutors suspect criminal negligence and opened an investigation in June, suggesting a stray cigarette butt or an electrical fault could be the culprit.

The culture ministry said in October that nearly €1 billion ($1.1 billion) had been pledged or raised for the reconstruction.