Republican Governor Jeff Landry signed the legislation which requires a poster-sized display of the Ten Commandments in “large, easily readable font.”

All classrooms from kindergarten to state-funded universities will be required to follow the new rule.

The posters will also have a four-paragraph “context statement” explaining how the religious texts “were a prominent part of American public education for almost three centuries.”

Classrooms must have the posters up by the start of 2025.

However, civil rights groups have promised to file a lawsuit to challenge the law, saying that religion should be kept out of government.

In a joint statement from the American Civil Liberties Union, Americans United for Separation of Church and State, and the Freedom from Religion Foundation, the groups said: "The law violates the separation of church and state and is blatantly unconstitutional.

"The First Amendment promises that we all get to decide for ourselves what religious beliefs, if any, to hold and practice, without pressure from the government.

“Politicians have no business imposing their preferred religious doctrine on students and families in public schools. "