Trierweiler's plane from India's financial capital Mumbai landed at 8:05 am and she was whisked away without having to go through the normal passenger terminal, an airport official said.
Her two-day visit to India on behalf of the French charity Action Contre la Faim (Action Against Hunger) saw her visit a slum and witness a feeding programme for malnourished children.
She said during the India trip that she would like to extend her humanitarian work -- "especially towards poor children".
The 48-year-old, who is still employed as an arts writer by the French magazine Paris Match, said she planned to continue charity work rather than returning to her previous role as a political journalist.
The prospect of covering Hollande would be "too complicated" she admitted at the end of the trip.