Artists from a dozen countries Tuesday launched an online campaign called "100 drawings for Jabeur" Mejri in support of the Tunisian jailed in 2012 for posting caricatures of the Prophet Mohammed online.
The launch of the campaign comes nearly two weeks after Tunisia adopted a new constitution that guarantees the right to freedom of conscience and expression.
"While freedom of expression and conscience are guaranteed in this founding text, the continued detention of Jabeur Mejri is contrary to the spirit and the text of the constitution," the support committee for Mejri said in a statement.
As part of the campaign artists have posted dozens of drawings and cartoons online (www.100dessinspourjabeur.org), some of which are aimed directly at Tunisian President Moncef Marzouki, who has failed to use his prerogative to pardon the young man.
A drawing by French cartoonist Large shows a guillotine marked "Marzouki" decapitating a pencil, while Tunisian artist "Willis from Tunis" depicts the president in front of a blackboard copying out lines that read: "I must get the innocent out of jail and put the criminals in there, and not the other way round".
Mejri, who comes from Mahdia, south of Tunis, is serving a seven-and-a-half year sentence for posting cartoons of the Prophet on his Facebook page.
Since the penal code does not punish blasphemy, he was convicted of transgressing morality, defamation and disturbing public order.
Mejri and his co-defendant Ghazi Beji, both unemployed and militant atheists, were charged with "publishing works likely to disturb public order" and "offence to public decency".
Beji fled abroad and was given asylum in France last June.
Marzouki had said on several occasions he wanted to free Mejri, but warned it would be difficult so long as Tunisia faced a rise in activity by jihadist groups.
"There are huge tensions, there is the fight against terrorism, I do not want this release to start debates. But I am going to free him, I am simply looking for the right moment, both for his own security and that of the country," Marzouki said in Paris last November.