RNA - The protesters fear that Zouheir Makhlouf, who walked free after being investigated for alleged sexual harassment and public indecency, will enjoy immunity from prosecution over any future allegations leveled against him by women.
"Stalkers shouldn't make laws," they chanted outside the inaugural session of the new parliament on Wednesday.
A video showing the mustachioed politician sitting in a car with his trousers dropped to his knees was shot last month by a pupil who shared it online alongside accusations of harassment.
Makhlouf, who was elected for the Qalb Tounes party of controversial media magnate Nabil Karoui, denies inappropriate conduct and has said he was urinating due to a medical condition.
But the video went viral sparking Tunisia's own #MeToo movement, with sex abuse victims breaking taboos under the hashtag #EnaZeda.
It was inspired by the huge global movement that bloomed in 2017 in the wake of sexual assault allegations by multiple women against Hollywood mogul Harvey Weinstein.
"Immunity is for your parliamentary duties not your sexual desires," read one placard waved by the demonstrators.
Article 68 of the Tunisian constitution provides that no sitting MP can be "arrested or tried for their opinions... or for actions taken in connection with their parliamentary duties," a formulation that in theory excludes allegations of sexual impropriety.
But "the interpretation of the law in Tunisia means that a lawmaker acquires an immunity that covers all of his or her actions, including those committed before they took office," said jurist Nour Jihene, who joined the protest outside parliament.
The protesters called for stricter implementation of a July 2017 law that outlaws sexual harassment in public places with a maximum penalty of a year in prison and a 3,000 dinar (1,000 dollar) fine.