"I don't have a personal fortune," she told Elle magazine in an interview published on Monday. "I need to earn a living. I have three children to take care of."
"Like millions of French women, my financial independence is a concrete reality and a priority," she said.
Trierweiler is a print and TV journalist, working at celebrity magazine Paris Match and on TV channel Direct 8.
Her relationship with Hollande began in 2005, although was conducted in secret as he was still living with his then partner, Socialist politician and former presidential candidate Ségolène Royal.
Trierweiler herself is twice-divorced. Hollande has four children of his own from his relationship with Royal.
The 48-year-old plans to continue working as a journalist, although recognises there will be some constraints on her with a partner as president.
"For several years at Paris Match I was covering culture rather than politics," she said. "I think I can carry on working as a journalist if I'm not covering French news. I could, for example, interview foreign celebrities."
One thing is certain. Trierweiler does not regard herself as merely decorative.
"I will not be a trophy wife," she told The Times.
Trierweiler knows that her new status will require some adaptation, but she is not yet sure what it will involve.
"I need to see what this role really needs and how I can fulfil it while staying active," she said.