Two French academics have launched a petition to remove a parliament mural commemorating the abolition of slavery, which they said was a racist, humiliating and dehumanising depiction of black people.

Mame-Fatou Niang, associate professor of French at Carnegie Mellon University in Pittsburgh, and Julien Suaudeau, who lectures in Pennsylvania, said the vast mural which has hung in a corridor of a building at France’s National Assembly for 28 years should be taken down. It was created in 1991 by French artist Hervé di Rosa to commemorate France’s first abolition of slavery in 1794.

“Its presence – in complete indifference – at the heart of one the highest sites of the Republic adds insult to injury,” the academics wrote in an open letter in L’Obs magazine. “It is historically unacceptable and politically incomprehensible. We demand the removal of this wall of shame.”

Facebook Twitter Pinterest Hervé Di Rosa in front of his mural at the National Assembly in Paris. Photograph: Benjamin Auger/Getty Images

Niang and Suaudeau said they understood that di Rosa’s style – a cross between comic art, kids art and science fiction – had often featured oversized lips. But they said, in this context, commemorating the abolition of slavery with black faces with big blue eyes and large lips was a “humiliating and dehumanising” vision reminiscent of old racist and colonialist imagery such as France’s Banania hot-chocolate adverts, the comic book Tintin in the Congo and the grotesque, grinning blackface imagery of America’s 1920s Coon Chicken Inn restaurants.

The petition comes shortly after students at Paris’ Sorbonne university cancelled a performance in which they were accused of using blackface.

Niang told the Guardian: “This artist is completely free to create his work. But I have a problem with this work being made to commemorate the abolition of slavery and being placed in the National Assembly. When you’re in front of a work of commemoration, you should be reflective – not angry or disgusted.”

She discovered the mural last year when she was invited to the French parliament to screen her documentary Mariannes Noires.

When Niang first shared her reaction to the mural on social media, a teenage French girl wrote to her, saying: “I saw it during a school visit, I was so shocked and the boys were giggling and I couldn’t understand what I was seeing. One of the teachers was lost for words. Another black teacher was angry.”

The French parliament press office said the National Assembly had not commented on the petition.

Suaudeau, who teaches at Bryn Mawr College in the US, said the fact that the mural had hung for so long without French lawmakers reacting showed a lack of awareness on race issues. “This is about exploring the blind spots of our history,” he said.

The artist Hervé di Rosa told Le Monde his reaction was one of “total incomprehension”. He said: “My characters – whatever their colour, gender or physical characteristics – have always had large red lips.” He told French TV he was “taken aback” by the petition.

Sophia Rosenfeld, a history professor at the University of Pennsylvania, who is an expert on the history of French democracy, told the Guardian: “The iconography of the state – and its chief sites – should reflect the state’s highest values. In a democracy like France that should include the essential dignity of all humans.”

She said: “The problem with the mural in the French parliament is that it rightly celebrates the abolition of chattel slavery while also denying dignity to those most affected by slavery’s horrors: peoples of African descent. That’s a pernicious message for the French state – or any state – to be conveying in 2019.”