It took just five minutes to film on her iPhone. But 2.1 million Facebook views later and Cécile Djunga’s emotional account of her first year as Belgium’s only black TV presenter has sparked a national debate about racism, drawn promises of a sea change in the representation of ethnic minorities in the media and led to an intervention from the prime minister.

Djunga, 29, a weather presenter on the French-language public service broadcaster RTBF, had not expected any of it. “If I knew it was going to go viral I would have made it shorter and done my hair,” she told the Observer on Saturday.

The video that has sent Belgium agonising over race – a reckoning that many believe has been a long time coming – had been intended as a light-hearted response to some of the more bizarre racist comments Djunga has endured since being announced in 2017 as the face of the weather on the channel La Une.

“If you want a good laugh, I’ve got a good one for you today,” she told her followers in last week’s post, before recounting the tale of a woman who had called in days earlier to complain that the presenter was “too black and all people could see were my clothes”.

Her colleague, tongue-in-cheek, had responded to the complainant that perhaps she could change the contrast on her television.

The racists are a minority. Belgium is behind – but it can change Cécile Djunga

Djunga laughs along in her film at the “absurdity” of it all, but her eyes well up. Something catches in her throat. “It doesn’t stop. I’ve been doing this job for a year and I’m fed up of getting tonnes of racist and insulting messages,” she said. “It hurts because I’m a human being.”

What started as a personal appeal has become a national debate. Galvanised by Djunga’s message, Belgium’s leading francophone paper Le Soir called for action. RTBF among others has promised greater diversity in the presenters that they recruit.

Djunga said on Saturday that she had not set out to provoke such a reaction. “I am not an activist. I am not a spokesperson. I just want to live my life,” she said. But, now it is here, she wants this moment to mean something.

“At first I did laugh,” she said, remembering the complaint that triggered the video. “It was too crazy. She couldn’t see me? What is this shit? I laughed about that and I wanted to make a video to talk about it to my followers. And then when I was filming I became angry and sad. I just felt very emotional. It was just suddenly too much.

“I have had this since I was born,” she said. “I think I am a strong person. If I wasn’t strong, I wouldn’t be there. But I am human. And this day it was too much. But I am pleased. Black people, but not just black people, are explaining their suffering. And we have to talk about that. We should not be ashamed.”

Responding to Djunga’s appeal, Charles Michel, the Belgian prime minister, has warned that it will be the bigots in Belgian society who will have reason to be fearful in the future.

Djunga also wants Belgium to get to grips with the old prejudices that linger in part, she thinks, because of failures in telling the truth about the country’s colonial past. Until the publication of Adam Hochschild’s book King Leopold’s Ghost in 1998, there was little discussion about the 10 to 15 million people killed in the Congo Free State, run as a personal fiefdom by King Leopold II, whose presence is everywhere in modern-day Brussels.

“In Belgium, people do not know anything about colonisation or immigration. They feel it is all the fault of foreigners. I think in Belgium we have a problem in that we never explained the truth about colonisation, and it should be told in the schools,” she said.

The storm of protest over the treatment meted out to Djunga has coincidentally come as the anti-immigration N-VA, the Flemish nationalist party, a coalition partner in the Belgian government, has been forced to distance itself from a youth movement exposed as a cover for a far right antisemitic group. The Belgian prime minister’s insistence that a TV presenter should not be targeted over the colour of her skin was accompanied by a vow to also tackle those who target Jews.

Djunga, from the Brussels suburb of Woluwe-Saint-Pierre – one of five daughters of an Angolan midwife and a Congolese hospital manager who came to Belgium 50 years ago for work – watched her parents suffer from racist attitudes.

Her own aspirations to be a Shakespearean actress were blocked, she believes, because of the colour of her skin.

But the outcry in the past few days offers her hope. “I think people were touched and were angry,” she said. “The racists are a minority. Belgium is behind – but it can change.”