The socialist elected official caused a surprise by announcing last weekend that the giant rings representing the five continents, which have been enthroned on the Iron Lady since June, would "stay" there after the Paralympic Games which end on September 8.
The idea, validated by the International Olympic Committee (IOC), owner of the Olympic logo, is to perpetuate a "historic moment", explained to AFP Pierre Rabadan, responsible for sports and the Olympic Games at Paris City Hall, which owns the Eiffel Tower.
"It is now inseparable from these moments of joy, pride and fraternity," adds the Paris city hall. Which invokes a "meeting between two ephemeral objects: the most famous monument in Paris, thought of as temporary when it was created in 1889, and that of the Olympic movement initially installed for the period of the Games."
"We are working on a plan of indefinite duration," explained Pierre Rabadan. The IOC is conducting a "feasibility study" to replace the current rings with lighter ones, so as not to damage the structure.
But many voices have been raised against this gesture which would "distort" the work of Gustave Eiffel. Starting with the descendants of the famous engineer, according to whom it is "not appropriate that the Eiffel Tower, which has become since its construction the symbol of Paris and by extension of France itself in the world, should see the symbol of an external organization added to it in a lasting way".
Trademark
The opponents' main argument: the rings, displayed at each edition of the Olympic Games on an emblematic monument of the host city - such as London's Tower Bridge in 2012 - are above all a commercial brand.
Keeping them is "a very bad idea, it doesn't go at all with the universal message of the Eiffel Tower which is a 'free' work", reacted Christine Nédélec, president of the heritage protection association SOS Paris.
"When the Eiffel Tower lights up in support of a country under attack, of victims... will we still uphold the positions of the IOC?" asks the leader of the centrist MoDem party on the Paris Council, Maud Gatel, recalling past controversies over the organisation of the Games in countries "not necessarily democratic", or criticism of the partnership with Coca-Cola.
The Iron Lady is "traditionally associated with happy or unhappy events, but in a temporary way. Installing the rings permanently would be unprecedented," notes Julien Lacaze, president of Sites & Monuments. In his eyes, this would be equivalent to forever attaching the famous comma of a major sports equipment manufacturer to it.
Another criticism is the lack of consultation.
"We can understand that Anne Hidalgo wants to prolong a state of political grace. But it's complicated to say 'yes' to a mayor who announces it all by herself!" laments a leader of the environmental group on the Paris Council, speaking on condition of anonymity.
The Eiffel Tower "is not Madame Hidalgo's personal coat rack," Benjamin Haddad, a Macronist MP from Paris, said on France 2.
Rachida Dati, the resigning Minister of Culture and opponent of the socialist mayor, tempered her rival's enthusiasm, by asking that "all procedures and consultations aimed at protecting heritage be respected" in advance.
According to Julien Lacaze, it is the French Ministry of Culture that will have the final say.
The 2019 Olympic law introduced an exemption to the ban on all advertising on monuments and historic sites. However, this exemption will end "15 days after the end of the Paralympic Games", underlines the association leader, who had the City of Paris condemned during the 2016 Euro football championship for "illicit advertising on the Champ de Mars", a vast public garden located near the Eiffel Tower.
The Eiffel Tower, one of the most visited monuments in the world, has been listed as a historical monument since 1964, but it is not classified. "We are fighting to have it listed and thus guarantee it greater protection," comments Corinne Roy, president of the Friends of the Champ de Mars.