Back at home, President Francois Hollande faced a new showing of discontent with his presidency as some 17,000 people marched through central Paris, angry at his handling of the stagnant economy, high unemployment and high taxes.
The ex-first lady arrived in Mumbai on Sunday night after a flight from Paris, in which she rode business class and cabin crew limited access to reporters also aboard the flight. She emerged looking tired, but smiling.
Trierweiler is on a long-scheduled humanitarian mission in India, which she maintained despite having just emerged last week from a weeklong stay in a hospital. Trierweiler was hospitalized with what aides described as shock and the blues after a French gossip magazine published images that it said proved Hollande was having an affair with an actress.
Aides said Trierweiler, a career journalist, is limiting her activities in India, and won't visit a Mumbai slum as scheduled. She is also scheduled to visit a nutritional center at a hospital and attend a news conference and gala dinner Monday, in conjunction with aid group Action Against Hunger.
"These last few days have been difficult. But today, she is serene," Trierweiler's chief of staff, Patrice Biancone, told The Associated Press on the flight from Paris. He said her office as first lady will be formally eliminated Wednesday.
The head of Action Against Hunger told the AP that Trierweiler planned to commit herself to humanitarian work.
Hollande, who has never married, announced the end of his relationship with Trierweiler on Saturday. They had been a couple since 2007, after Hollande ended more than a two-decade relationship with the mother of his four children, former presidential candidate Segolene Royal.
In an interview published Sunday and conducted before he'd split with Trierweiler, Hollande renewed his plea for privacy. He told Time magazine that "private life is always, at certain times, a challenge. And it has to be respected."
Hollande's approval rating in France stands at about 30 percent, and protesters from about 50 organizations took to Paris streets Sunday with banners saying "The French are angry!" But few mentioned his private life, instead focusing on economic issues.
"Today they are taking our money from all sides. There are new taxes all the time. We have had enough!" protester Johan Bonnain said.
Sohrab Monemi and Greg Keller in Paris contributed to this report.