French health authorities said one person was suspected of contracting a deadly new SARS-like virus after coming into contact with a man confirmed to be infected, following tests that cleared another three patients.
"Further examinations are necessary" to determine if the patient has come down with the deadly novel coronavirus, the health ministry said in a statement.
The patient shared a hospital room with a 65-year-old man who is in intensive care in northern France after being diagnosed with the virus that has killed 18 people, mostly in Saudi Arabia.
The regional health authority said the man, who was hospitalised after returning from a holiday in Dubai in April, was being treated in isolation in a "very serious but stable condition".
The virus, known as nCoV-EMC, is a cousin of Severe Acute Respiratory Syndrome (SARS), which triggered a scare 10 years ago when it erupted in east Asia, leaping to humans from animal hosts and killing some 800 people.
It was first detected in September 2012 and since then more than 30 cases have been reported in different countries, with 18 deaths.