Journalist Marilyne Dumas was reporting as the arrest took place
A live television broadcast captured dramatic scenes when plain-clothed security forces entered the headquarters of Tunisia's bar association to detain a lawyer on Saturday.
Sonia Dahmani was wanted in connection with comments she had made earlier in the week about the situation in Tunisia.
As her arrest took place people can be heard shouting: “Lawyers are free, from the police they are free!''
There has been growing criticism of restrictions on free speech imposed under the presidency of Kais Saied.
On Friday, Ms Dahmani had refused to attend a court hearing to explain why she questioned that sub-Saharan migrants would want to settle in Tunisia, her lawyer said.
Then on Saturday, during a live France24 broadcast, reporter Marilyne Dumas can been seen at the bar association headquarters where Ms Dahmani was thought to be.
Dumas then stops mid-sentence as masked men come into shot and force their way into an office. A short while later people can be heard screaming and shouting as the masked men leave.
Someone then approaches the camera to try and shut it down and Dumas is heard saying: "We are in a public place, you do not have the right to do that."
France 24 has condemned was it called a "brutal intervention by security forces that prevented journalists from practising their profession as they were covering a lawyers' protest for justice and in support of freedom of expression".
On Sunday, two journalists were arrested over critical comments they had made, a lawyer told the AFP news agency.
The basis for these arrests and Ms Dahmani 's detention is thought to be a controversial law known as Decree 54 which the president signed in September 2022.
The authorities said it was introduced to fight fake news but critics say it is very vague and those found guilty of defamation or insult can face five years in prison.
Some 60 journalists, lawyers and opposition members have been held under the decree, AFP quotes the National Union of Tunisian Journalists as saying.
There was a protest on Sunday in the capital, Tunis, calling for the release of those being held.
President Saied came to power in 2019 after free elections, but in 2021, he sacked the prime minister and suspended parliament.
The following year a new constitution was approved in a referendum that critics said risked the return of authoritarian rule to the country.
Mr Saied has justified his actions by saying he needed new powers to break a cycle of political paralysis and economic decay.
