The President is being sued by 3 protesters who claim they were demonstrating outside the White House at Lafayette Park on June 1 -- the day POTUS took his now-infamous church photo-op.

According to the lawsuit, obtained by TMZ, the protesters claim they were part of a peaceful demonstration and the dispersal warnings to the crowd were not clear or intelligible. They say all of a sudden officers in riot gear charged them with their batons, firing rubber bullets and using pepper spray.

In the docs, the protesters claim the crowd-clearing tactics violated their constitutional rights, including freedom of assembly under the First Amendment and their right to be free from excessive force under the Fourth Amendment.

In fact, they invoke the words of President Franklin D. Roosevelt saying June 1 is "a day that will live in infamy."

The protesters also claim the Trump Administration later lied about the amount and kinds of force used to disperse the crowd.

According to the suit, the protesters want an injunction allowing them to exercise their right to protest without fear of retribution and to restore access to Lafayette Park, which has since been closed off by fences.

The protesters also want a finding that the use of tear gas, flash-bang grenades, smoke bombs and rubber bullets was unconstitutional.

Oh, and in addition to President Trump, they are also suing Attorney General Bill Barr, Secretary of Defense Mark Esper and D.C. National Guard Commander General William Walker ... and they want damages for injuries.