Ben Brik left the north-west Siliana prison at 6.00 am and headed for nearby Tunis.
"I'm free once more and I plan to go to Paris," he told the AFP news agency shortly afterwards.
"I'm going to see my friends, everyone who supported me," Ben Brik said, adding that he would be talking to editors about a book based on his time in Siliana, which he describes as Tunisia's toughest prison.
Ben Brik was sentenced to six months' imprisonment after being convicted in November 2009 for assaulting a woman during a traffic incident.
"It's a farce and everyone knows it," he said on Tuesday.
He has always maintained that the authorities framed him in an attempt to silence his outspoken criticism of President Zine El Abidine Ben Ali and his government.
Ben Brik dismisses a complaint filed against him by a Tunisian woman in France as "a similar plot".
The journalist is a well-known figure in France, where newspapers have published several of his reports on human rights abuses in Tunisia.