The city of Boston is facing a religious discrimination suit for banning a Christian flag while allowing 284 other flags to fly at an event, according to a federal lawsuit filed last week.

The city was asked to fly an inter-denominational Christian flag on Constitution Day on September 17, 2017, for an hour-long event, but the city refused on the grounds that only secular flags could be flown at the event.

“There’s no question that it is an unconstitutional act and originally said it was a violation of the First Amendment, which I find ironic,” Hal Shurtleff, the director and co-founder of Camp Constitution, told Fox News. “I’m optimistic the lawsuit will go our way.”

The organization had been planning an event where pastors would encourage Christian values and end it with the presentation of that Christian flag, but the event had been canceled after the city rejected the flag.

When Camp Constitution tried to plan the event again the following year in 2018, the city decided to reject the usage of the flag once again.

A federal court and an appeals court both ruled against Camp Constitution the past few years, but the group’s latest lawsuit filed against the city states that the city of Boston “may have violated the Establishment Clause” of the U.S. Constitution by allowing the flag of the Catholic Church.

According to the latest suit filed in the U.S. District Court for the District of Massachusetts:

Yet, despite all of these many flag raisings containing religious symbols and imagery, and the City’s allowing the official flag of the Catholic Church, Camp Constitution’s proposed flag raising was denied because it was ‘religious.’ There can be no dispute that the City’s denial impermissibly discriminated between religion and non-religion, and discriminated between religious sects. Both violate the Establishment Clause.

Mathew Staver, the founder and chairman of Liberty Counsel who also represents Camp Constitution, slammed the city of Boston for snubbing them three times in a row.

“Censoring religious viewpoints in a public forum where secular viewpoints are permitted violates the First Amendment,” Staver said.

“Boston city officials may not ban the Christian flag as part of a privately-sponsored event when they allow any other flag by numerous private organizations. It’s time for the court to stop the city’s unconstitutional censorship,” added Staver.