There are three "Yves Langlois" on the public scene in Canada: one is a film director, the second is a film editor, and the third has been a member of the Front de Libération du Quebec (FLQ). This article discusses the third.

Yves Langlois, a.k.a. Pierre Seguin, born in 1947, was a member of the Quebec terrorist group calling themselves the Front de Libération du Quebec (FLQ) and responsible for terrorist operations during the 1970s in Quebec.

He was arrested in France for possession of illegal firearms and served 2 years in a French prison, where he may have learned the skills he later used in bomb-making, assassination and kidnapping. In August of 1970, he and other terrorists from Quebec traveled to Jordan to train with Palestinian commandos. At the same time, members of their group in Montreal announced they would begin a policy of "selective assassination."

Langlois was a member of the Liberation Cell of the FLQ that kidnapped James Cross, the British Trade Commissioner to Canada, triggering the 1970 October Crisis. The Liberation Cell threatened to execute Cross, making demands that included money and the release of other convicted terrorists. The kidnappers eventually negotiated Cross's release without achieving any of their goals except safe passage out of Canada for themselves: Langlois and four others were granted refuge in Cuba. However, in 1974, a report from the Canadian embassy in Paris, France indicated that Langlois was living in Paris.

Langlois returned to Quebec in June of 1982. He was arrested and charged for his crimes and on September 27, 1982 he was sentenced to two years in prison less one day for his part in the kidnapping of James Cross. On July 19, 1983—less than one year later—he was released on parole.