The journalist took revenge on Hollande for spurning her for actress Julie Gayet with a sensational 2014 kiss-and-tell memoir called Thank You for This Moment, which all but sank Hollande's presidency.
The book became an instant bestseller, and Hollande, a Socialist, never lived down his alleged references to the “toothless” poor.
Trierweiler, 55, had worked for the glossy weekly as a political correspondent, interviewer and columnist for three decades.
j'ai appris en plein cœur de l'été et pendant mes congés de façon extrêmement brutale mon licenciement de Paris Match où je travaillais depuis trente ans. Ce licenciement sans aucun motif valable me laisse en état de choc et de sidération. #parismatch
— Valerie Trierweiler (@valtrier) August 13, 2020
“I discovered in the middle of my summer holidays in an extremely brutal way that I have been sacked from Paris Match after 30 years,” Trierweiler said on Twitter.
“This sacking was for no reason and has left me shocked and astonished,” she added.
Trierweiler was famously admitted to hospital after Hollande's affair was revealed by paparazzi images of his nightly visits by scooter to Gayet's apartment.
The politician had tried to portray himself as a safe pair of hands “Mr Normal” in contrast to his mercurial predecessor, Nicolas Sarkozy.
As well as spending most of her career at Paris Match, Trierweiler also interviews politicians for the French television channel Direct 8.