Tunisians demonstrate against the return of extremists
Protesters waved Tunisian flags and chanted: "No to freedom for terrorist groups!"
They slammed Rached Ghannouchi, head of the Islamist Ennahda party, who has in the past supported the idea of allowing Tunisian militants who "repent" and renounce violence to return home.
One of the protesters, Faten Mejri, said "For us, they are not Tunisians. They are awful people."
Banners at the protest in front of Parliament in Tunis read "Close the doors to terrorism" and "No tolerance, no return."
Organisers said some 1,500 people attended the rally.
The protest was promoted by the deadly truck attack in a Berlin Christmas market by Tunisian Anis Amri, who had pledged allegiance to Islamic State [IS] group and was killed on Friday in a police shootout.
Amri, 24, was slated to be deported home from Germany.
Earlier this month, President Beji Caid Essebsi said Tunisia would refuse to pardon Tunisians who fight for militant organisations
"Many of them want to return, and we can't prevent a Tunisian from returning to his country," he told AFP, "but we will be vigilant."
There are more than 5,000 Tunisians fighting for militant groups abroad, mainly in Iraq, Syria or neighbouring Libya, according to a UN working group on mercenaries.
At least 800 Tunisian extremists remain under surveillance since returning home after fighting aboard.
Since its 2011 revolution Tunisia has faced repeated militant attacks, killing more than 100 soldiers and policemen, as well as about 20 civilians and 59 foreign tourists, according to official figures.
Agencies contributed to this report