Notre-Dame Cathedral in Paris is being sued by French language purists for only translating its signs into English.

The group has already succeeded in forcing the Eiffel Tower to add Spanish to its information signs alongside English and French.

The Association for the Defence of the French Language claims that only translating signs into English helps increase the international dominance of that language.

It has French law on its side -- an oft-ignored 1994 regulation requires all public buildings to translate all their signs and information into at least two languages.

The association filed a complaint against Notre-Dame with a Paris court on Monday, demanding the change.

It says the Eiffel Tower agreed in November to add Spanish after it threatened similar legal action.

Many of the panels explaining the ongoing reconstruction of Notre-Dame following a devastating fire in 2019 are written in French and English.

"If there is a foreign language, it is always Anglo-American," bemoaned the association's spokesman Louis Maisonneuve (speaking, of course, in French).

He insisted on differentiating "Anglo-American" from English, and says it is always the first choice of French authorities -- for instance in the use of "downtown" instead of "city centre".

"The law protects French because it promotes linguistic pluralism," Maisonneuve said.

The association is targeting 20 other public bodies, including the national post office over the name of its banking service, "Ma French Bank".