The four workers, who had been employed for the summer by the town of Genevilliers just outside Paris, to help run a sports camp in southwestern France, were dismissed on July 20, the first day of Ramadan, after being told they were endangering children's safety by not eating or drinking between dawn and dusk.
They are now planning to contest their dismissal through France's labour courts and the French Council of the Muslim Faith (CFCM) said on Tuesday it was considering suing Genevilliers council for discrimination.
In a statement, the Communist mayor of Genevilliers defended the decision to suspend the employees on health and safety grounds after an official who visited the camp noticed that they were not eating or drinking at lunchtime.
"They did not respect the terms of their contract in a way that could have endangered the physical safety of the children they were responsible for," the statement said.
"This lack of nourishment and hydration could have resulted in these employees not being in full possession of the means required to ensure activities at the camp were correctly and safely run, as well as the physical safety of the children in their charge."
Nicole Varet, an aide to the mayor, said the decision to dismiss the four employees had been influenced by an incident three years ago in which a fasting camp worker had been taken ill whilst driving, resulting in an accident in which a child was seriously injured.
But Mohand Yanat, a lawyer representing the four sacked workers, said the safety argument was a smokescreen for anti-Muslim prejudice.
"How can you judge the capacity of someone to do their job on the basis of their religious practice?" he asked.
Abdallah Zekri, a spokesman for the CFCM, echoed his remarks. "Religious freedom is a fundamental right and you cannot in any circumstances ban someone from practising their religion," he said.
One of the four workers, who was only prepared to be identified by his first name, Samir, said he hoped the action they are planning to take would make life easier for other Muslims.