French pressure groups have demanded an end to the dominance of the English language in business in France.
Vive la langue francaise! Many are sick of speaking English
A group of trades unions and language lobbyists say the French language is being reduced to a local dialect.
They have organised a press conference in parliament to demand the right to work solely in French.
One campaigner has dubbed the battle to preserve the supremacy of the French language as a fight against "linguistic hegemony" of English.
"We can no longer tolerate this," said Albert Salon, president of the French-speaking campaigning group, Forum Francophone International.
"We are not against influences of one language by another, or the occasional borrowing of words, but now there is a wholesale substitution of the French language for English."
He said in many companies it had become standard practice for native French speakers to use English even among themselves and French scientists were forced to publish their research, in English, in leading US journals.
"We have nothing against the Brits or the Americans," Mr Salon said.
"But we simply cannot accept that our language is reduced to a local dialect - we are protesting against this linguistic hegemony!".
A recent survey showed that seven percent of French firms used English as their main language and multinational companies often sent e-mails in English to their French employees.
But Pierre Kosciusko-Morizet, CEO and founder of French site Priceminister.com, accepts that having English as a global business language enables him to converse with foreign colleagues in a common tongue.
"Some things are facts and you can't fight against them," Mr Kosciusko-Morizet said.
"We can promote French but I don't see very efficient ways of fighting English. English didn't become the global language of business by fighting other languages," he added.
The BBC's Caroline Wyatt, in Paris, says that President Jacques Chirac is one of the most ardent supporters of those who wish to protect the French language - he once walked out of a meeting in Brussels when a Frenchman began his speech in English.