A post on social media had claimed that 30% of the hospital's medical workers have not yet received a COVID-19 vaccine and were facing suspension.
A hospital in France has denied claims around a third of its medical staff has still not received a COVID-19 vaccine.
A politician had suggested that around 30% of doctors and nurses at CHU Nantes had not been vaccinated.
But the hospital has stated that "almost 100%" of its workers had received a jab.
French medical workers who have not received at least one dose of a coronavirus vaccine now face suspension from work.
President Emmanuel Macron had told medical professionals and those working with vulnerable people must get the jab by September 15, in an effort to boost vaccination uptake and protect patients from infection.
Around 3,000 staff in health and social care facilities were suspended on Thursday, the first day after the deadline passed. Some hospitals had raised concerns that staff shortages would add to their strain.
According to the latest figures from Santé Publique France, 89.3% of the country's nurses had been inoculated, and 95.0% of independent staff.
A report about the university hospital in the western city of Nantes was spread by Florian Philippot, a former French MEP and founder of the Eurosceptic Patriots party.
Philippot falsely claimed to his 278,000 followers on Twitter that a proportion of staff at CHU Nantes had not been vaccinated. The tweet has been shared more than 2,000 times.
"CHU Nantes: 30% of the care workers have not yet received any dose of vaccine," he wrote on Twitter.
But the university hospital has rejected the claim and says only 1% of its staff are yet to be vaccinated.
"The day after the implementation of the compulsory vaccination for hospital staff, the Nantes University Hospital is pleased to note that almost 100% of the professionals in our establishment have been vaccinated against COVID-19," a spokesperson told Euronews.
"Indeed, to date, only 91 professionals, out of nearly 13,000, have not fulfilled their vaccination obligation and are therefore suspended until further notice.
"Each suspended professional will be received and accompanied to settle their individual situation."
Majority support for the vaccine mandate
The spokesperson at CHU Nantes also told Euronews that more than 11,300 medical workers at the facility has been fully vaccinated.
"We would like to thank all the professionals for their unfailing mobilisation ... in the vaccination against COVID-19," the statement continued.
"This approach is the only way out of the crisis, in the service of the community and first and foremost the protection of the most vulnerable."
"Once again, the public hospital service is demonstrating its commitment and its ability to be at the forefront of the response to the health crisis."
CHU Nantes also stated that all staff are still required to wear masks on the premises and carry COVID-19 health passes.
Polls have suggested that most people support the vaccine mandate for medical staff, but critics have regularly protested against the measure.
On Tuesday, some medical professionals burned their diplomas at a protest in Paris against compulsory vaccines.
Around 84% of French adults are now fully vaccinated, and the country has also opened vaccinations to children aged 12 or over and started giving booster shots to vulnerable people.