"We are experiencing a moment of profound sadness. List Renaissance is naturally joining this moment of national unity. We are suspending the campaign until further notice," Nathalie Loiseau, a candidate on the electoral list Renaissance said on Twitter.
The remark comes after Monday's fire left the cathedral heavily damaged. French President Emmanuel Macron has described the incident as a "terrible tragedy" and promised to rebuild the 850-year-old cathedral.
The French heritage foundation has launched a fundraising campaign, while a number of foreign officials have offered condolences and support to France. People in Moscow and Washington have brought flowers to the French embassies in their respective cities.
READ MORE: WATCH Emmanuel Macron Enter Notre Dame Cathedral as it Burned
The European elections will take place on 23-26 May.