A building in the suburb of Cergy-Pointoise, to the north west of Paris was cordoned off on Thursday after the alarm was ras raised that at least one person had fallen ill with 'Ebola-like symptoms".
It was reported the sick person had recently visited Guinea, one of the countries in West Africa hit badly by an Ebola outbreak that has killed thousands.
The prefect of Val-d'Oise Jean-Luc Nevache said the building was cordoned off so checks could be carried out and the move was made "as a precaution".
Accordng to RTL radio, around 60 people, some of whom recently visited Guinea, were effectively quarantined and a security cordon was set up around the building. Those inside were asked to remain where they were.
However later in the evening Nevache confirmed that the "suspicion was over" and the workers were allowed to leave.
Le Parisien newspaper reported that the alarm was raised when one of four people "of African origin" who had recently visited Gunea fell ill in the building and two others showed flu-like symptoms.
Those four were kept separate while medical tests were carried out to determine whether fears they had been infected by Ebola proved true, but authorities later confirmed the tests were negative.
France is on high alert to prevent the spread of Ebola. The government insists that it is ready to cope in the case of an outbreak but none have been reported up until now.
A French nurse who contacted Ebola in West Africa was recently cured of the disease after returning to France for treatment.
A Spanish nurse, who contacted the disease after treating an Ebola patient remains in a critical condition in Madrid.
France announced on Thursday that it will step up health checks at airports in the West African countries hit by the virus to try and prevent it spreading.
Fears are high that it is only a matter of time before someone is infected with the disease in France, with scientists from the UK suggesting that there was a 75 percent chance Ebola will arrive in France before the end of the month.
More to follow