Authorities took the step of closing access to the Georges Pompidou European Hospital in the south western edge of the city at around 4pm.
"Emergency arrivals are being redirected towards other hospitals in Paris," said the city's hospitals authority AP-HP.
"Staff have been informed to raise the alarm about anything unusual within the hospital or the presence of any suspect package," the authority said in a statement.
Images posted on Twitter appeard to show scores of people leaving the hospital building.
Within the hospital the movement of patients is being restricted and Europe1 reported that part of the hospital had been evacuated.
"The police are informed and are in the process of intervention," said the statement from AP-HP.
While little information has been given about the call, Europe1 radio claimed it was a bomb threat.
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