Tennessee's first-of-its-kind law that requires businesses and government facilities to post signs if they let transgender people use multiperson public bathrooms of their choice has been hit with another legal challenge.

Mike Curb, founder of Curb Records in Nashville and California's former lieutenant governor, filed the federal lawsuit Wednesday. In the complaint, Curb argues that the law violates his First Amendment rights because he is being forced to use the state's "discriminatory message."

Last week, the American Civil Liberties Union filed a separate lawsuit arguing similarly that the law illegally requires businesses to "communicate a misleading and controversial government-mandated message that they would not otherwise display."

The ACLU suit names the state fire marshal, state codes enforcement director and two district attorneys as defendants. Meanwhile, Curb's suit names Gov. Bill Lee, Attorney General Herbert Slatery and Nashville District Attorney Glenn Funk.

A spokesperson for Slatery said his office will represent the state but declined to comment further.

Funk, who is also named in the ACLU lawsuit, has said his office "will not promote hate" and won't enforce the law.

With the threat of misdemeanor penalties, the law requires that the following sign be posted in bold, uppercase letters outside public multiperson bathrooms, locker rooms or changing rooms wherever transgender people are not prevented from using the facilities of their choice: "This facility maintains a policy of allowing the use of restrooms by either biological sex, regardless of the designation on the restroom." It's one of five new Tennessee laws this year that have drawn backlash from LGBTQ advocates.

The law went into effect Thursday. However, it's unclear if and how it will be implemented throughout Tennessee. In June, Republican Senate Speaker Randy McNally told reporters he doesn't think the requirement will be enforced.

"The enforcement of that will be at the local level. We'll watch and see how that goes," Lee, a Republican, told reporters this week.