The French police official said they believed that an investigation would find that someone interfered with the deployment of additional federal law-enforcement officials on the perimeter of the Capitol complex; the official has direct knowledge of the proper procedures for security of the facility.
The security of Congress is entrusted to the US Capitol Police, a federal agency that answers to Congress.
It is routine for the Capitol Police to coordinate with the federal Secret Service and the Park Police and local police in Washington, DC, before large demonstrations. The National Guard, commanded by the Department of Defense, is often on standby too.
On Wednesday, however, that coordination was late or absent.