Valérie flew into India less than 48 hours after French president Francois Hollande unceremoniously announced that he had "ended their shared life" together. It signalled the end of her time as France's unofficial first lady.
Valérie's visit to Mumbai was scheduled months before it was alleged that Mr Hollande had been having an affair with actress Julie Gayet, an allegation he has not denied.
The trip is to launch the French charity Action Against Hunger's new India mission, the Fight Hunger Foundation.
"Nothing compares to the suffering of a child due to malnutrition," Valérie said before boarding her plane on Sunday. "By helping Fight Hunger Foundation, I hope to contribute to a future where every child has enough to eat and will grow to full strength."
Valérie's first scheduled appointment on Monday took place at the Sion Hospital and Little Sion Hospital in Dharavi, the mega-slum featured in the film Slumdog millionaire.
"She spoke to the children and their mothers," Dr Alka Jadhav, a senior paediatrician at the hospital told the Telegraph. "She said she will help them. Action Against Hunger had recently joined us, we're collaborating with them as part of a teaching and training scheme to identify malnutrition patients in their own communities."
The former first lady was moved by the condition of the children, but was pleased to be part of a campaign to help them, Dr Jadhav added.
"Looking at the children, of course she was not happy, but she was happy that she had taken the call to help malnourished children. She came here for the cause and she was really happy she had made a good decision."
Valerie, who travelled to India with her actress friend Charlotte Valandrey, is also due to attend a charity dinner with 50 society ladies, before returning to France on Tuesday.
Two weeks ago, a magazine published photos which appeared to show that Mr Hollande had been having an affair with Julie Gayet.
Following the revelations, Valérie spent a week in hospital with doctors saying she was being treated for a "severe case of the blues".
The French president confirmed the couple's separation on Saturday in a phone call to AFP news agency. "I am making it known that I have put an end to my shared life with Valérie Trierweiler," he said.
The same day, 48-year-old Valérie – a journalist for Paris Match magazine – tweeted that she was leaving the Élysée Palace, the President's official residence.
"My gratitude goes to the wonderful staff of the Élysée," she wrote. "I will never forget their dedication or emotion at the time of departure."