Pham Minh Hoang, who also possesses French citizenship, departed on a Vietnam Airlines flight from Ho Chi Minh City after being detained late Friday, said his wife Le Thi Kieu Oanh, who slammed the government's move as an act of "inhumanity."
On May 17, President Tran Dai Quang revoked Hoang's Vietnamese nationality on the grounds that he was involved in propaganda against the state.
"My husband left Vietnam at 11:30 last night [local time], on a direct flight to Paris," Oanh told the Agence France-Presse news agency Sunday.
"I feel totally defeated ... when my husband left, I couldn't say any farewell words, I also feel very angry," she added.
The French embassy in Hanoi confirmed Hoang's departure from Vietnam.
In 1973, the now 62-year-old activist moved to France where he stayed for 27 years. He returned to Vietnam as a mathematics lecturer at the Polytechnic University in Ho Chi Minh City. Hoang told AFP earlier this month he had come back to take care of his disabled brother and elderly mother.
Intimidation of activists
In 2011, Vietnamese authorities convicted Hoang of "attempted subversion" for publishing a series of articles that prosecutors said were aimed at overthrowing the government.
Released from jail after 17 months, Hoang remained under house arrest for three more years, but continued to write critical essays against the government controlled by a single party.
Hoang told the Deutsche Presse-Agentur news agency on June 14 that his lawyers were considering appealing against the revocation of his citizenship and that he had written a letter to French President Emmanuel Macron seeking his help.
While rights activists in Vietnam face pressure from authorities, revocation of nationality is unprecedented in the Southeast Asian nation.
A new report by Human Rights Watch (HRW) released earlier this week details dozens of violent assaults on rights activists and bloggers in Vietnam. Titled "No Country for Human Rights Activists," the report details 36 assaults committed by masked "thugs" between January 2015 and April 2017. Many of them were reportedly carried out in the presence of police.
shs/jlw (AFP, dpa)