Teachers are furious at a decision by the Louvre to end their right to free admission.
From September, like everyone else, they will have to pay 8.50 euros (pound;5.50) to visit the legendary art museum - unless they have taken at least one school trip there during the year.
The Louvre, which displays Leonardo's Mona Lisa, has presented the change as part of its effort to build better links with educators. It hopes to encourage teachers to bring pupils and aims to raise the number of young visitors from 500,000 to 600,000 a year by 2006.
Art teachers will still have free access to the galleries, but other teachers will have to bring a class to the museum to get their Louvre teacher's card, valid for a year, which gives them unlimited access for no charge.
The biggest teacher union, the FSU (Federation Syndicale Unitaire), has issued a strong protest. Gerard Aschieri, general secretary, said in a letter to education minister Francois Fillon that the move was "unacceptable and probably counter-productive to the link between teachers and national museums".
It took "no account of the role of museums in the personal training of teachers or characteristics of our job; it can only be regarded as an unfair and arbitrary meanness", he wrote. The FSU also noted that local museums had the right to limit free admission to, for example, teachers from the local area, but national museums, such as the Louvre, had remained free.
Forcing teachers to bring children to the Louvre in exchange for their free entry was moving them from being "representatives of culture in general, to representatives of the Louvre", it claimed, "a logic that was purely mercenary and scandalous".