Paris Mayor Bernard Delanoe has described a Russian Orthodox church to be built along the River Seine as an example of "hodgepodge architecture" not worthy to be on display near the Eiffel Tower.
Delanoe said the project - a gleaming white church with five traditional golden domes topped by an wavy glass roof linking it to a nearby Russian spiritual and cultural centre - was "mediocre architecture conceived in haste".
The project, whose design was chosen in an international architectural competition, was agreed in 2010 by Presidents Nicolas Sarkozy of France and Dmitry Medvedev of Russia.
Moscow has already purchased a plot of land for it on the left bank of the Seine, just across the river from the tunnel where Britain's Princess Diana died in a car crash in 1997.
"I want to express my very firm opposition to this project conceived by the French and Russian states without the agreement of the city of Paris," Delanoe said in a statement this week.
"I would like UNESCO, the guardian of the banks of the Seine, to get involved so no permission can be given without the endorsement of international experts," he said.
Paris-based UNESCO, the United Nations Education, Scientific and Cultural Organisation, has granted world heritage status to the banks of the Seine and the various styles of French architecture adorning them.
Delanoe's statement on Monday said the project's "hodgepodge architecture displays an ostentatiousness unsuited to a UNESCO world heritage site, or one within view of the Eiffel Tower".
A Russian presidential spokesman in Moscow said the Paris mayor could not block the decision made by the French president.
"This is his personal opinion ... and it has no legal significance," Viktor Khrekov told RIA-Novosti news agency on Tuesday.
With its 165 million members, the Russian Orthodox Church is the second-largest in Christianity after the 1.3-billion strong Roman Catholic Church.
It has been playing an increasingly active role at home and abroad since the end of Soviet communism in 1991.