The local authorities in Nice have refused a request by French anti-terror police to destroy CCTV images of Bastille Day attack last week in which a man drove a truck into a crowd, killing 84 persons.
The Paris prosecutor's office said the request had been made to avoid the "uncontrolled dissemination" of images, BBC reported on Friday.
"But officials in Nice have responded by filing a legal document, arguing the footage could constitute evidence," the report said.
In the aftermath of the attack in Nice, disagreements emerged over the scale of police and security force protection around the Promenade des Anglais at the time the attack took place.
France on Thursday ordered an investigation into the security arrangements at the July 14 Bastille Day celebrations.
Dogged by criticism over alleged security failure, French Interior Minister Bernard Cazeneuve called on the national police inspectorate to lead an inquiry to shed light on the security measures at the Bastille Day celebrations, Xinhua news agency reported.
"This is the first time we are asked to destroy evidence," French newspaper Le Figaro quoted a source as saying.
"The CCTV department and the city of Nice could be prosecuted for this, and also the officers in charge do not have jurisdiction to engage in such operations [to delete material]."
The paper said police and prosecutors wanted footage of the attack destroyed to preserve the dignity of victims and so it could not be used by jihadists for propaganda purposes.
But the French government has faced growing criticism about the extent of security measures and some reports have suggested the CCTV footage may show where and how police were deployed.
Meanwhile, President Francois Hollande announced on Friday that France would send artillery to Iraq next month for the fight against IS.
France has been conducting air strikes against IS and providing military training but is not committing ground troops.
