Grace Mugabe appeared at the Harare annual agricultural fair, smiling and stopping to chat with exhibitors as she toured stands alongside her husband, an AFP correspondent witnessed.
South Africa's main opposition, the Democratic Alliance, has also approached the courts asking it to declare the immunity "wholly without legal merit" and "unconstitutional".
Police had placed border posts on "red alert" to prevent Mrs. Mugabe from leaving but South Africa's global relations minister said she had granted diplomatic immunity to the wife of Zimbabwe's 93-year-old President Robert Mugabe.
Engels' lawyers this week filed a court injunction to try to annul the government decision to grant Grace Mugabe diplomatic immunity.
The DA, led by Musi Maimane, said it was clear that Grace was granted immunity simply to shield her from being tried in a court of law for her assault on Engels and two others on August 13.
She flew out of the country under the cover of darkness at the weekend after Nkoana-Mashabane controversially granted her diplomatic immunity. The Minister of International Relations chose to grant her diplomatic immunity.
Winslet, DiCaprio quote 'Titanic' lines to each other
By now, we're all aware of the deep and lasting friendship Leonardo DiCaprio and Kate Winslet formed on the set of Titanic more than 20 years ago.
"We think that was illegal, it was irrational and that there's nothing in her position as a private citizen seeking medical aid in South Africa to qualify her for diplomatic immunity".
On Friday, Mugabe made her first public appearance since leaving South Africa where she was charged with assault.
Harare has made no official comment on the issue and requests for comment from Zimbabwean government officials have gone unanswered.
She was not an official member of the delegation accompanying the Zimbabwean president to a Southern African Development Community summit in South Africa.
"There is nothing in either South African or worldwide law which renders her deserving of diplomatic immunity".
Advocacy group Afriforum has given legal backing to the alleged victim, Engels, and is working on the case with Gerrie Nel - the prosecutor who secured a murder conviction against Olympic and Paralympic runner Oscar Pistorius.
- Barguil exclu de la Vuelta
- Premier League clubs spend record £1.17bn in transfer window
- Right wing group cancels San Francisco rally over violence warnings
- Evacuation order issued near Kelowna as new wildfire breaks out
- Lamborghini dévoile un smartphone Android à 2 450$ !
- Google dévoilerait les nouveaux Pixel le 5 octobre
- Trump's response to Charlottesville just got brutal reviews
- Gorkhaland Agitation: IED blast at Sukhiapokhri police station, two injured
- Pep Guardiola turns to Raheem Sterling for more goals
- Crise ouverte avec la Pologne — Diplomatie