 To protect both the fabric of the building and the works of art it  contains, the productions use of the Louvre Museum in Paris was  carefully controlled. For instance, no equipment was allowed inside  the Louvre during the opening hours, so filming took place at night.  Since the crew were not permitted to shine light on the Mona Lisa, a  replica was used to film instead. No blood or mysterious writings  were permitted on the wooden floor of the museum so these scenes  were shot at Pinewood Studios outside London. In the end, 5 replicas  of the Mona Lisa were used.