'I was playing at mass when the fire broke'
Organist Johann Vexo was evacuated from Notre-Dame when fire alarms sounded.
He had performed at the cathedral for many years and said was "a part of my life which is destroyed".
The 850-year-old gothic landmark was extensively damaged when the blaze took hold on Monday.
President Emmanuel Macron has vowed the cathedral will be rebuilt "even more beautifully".