Teleperformance lost more than 14.9% before the stock was suspended at 09:57 on the Paris Bourse.
Trading resumed at around 10:40 GMT. At 10:51 GMT, the stock was down 27.3%, while the CAC 40 was eroding 0.08% at the same time.
Two market operators cited rival Klarna's deployment of an AI-based voice assistant as the reason for the call center group's fall.
The assistant, the result of a partnership with OpenAI, was deployed a month ago, Klarna explained in a press release.
It performs the work of 700 full-time employees and is expected to boost the group's profits by $40 million in 2024, the release said. (Reported by Danilo Masoni, written by Corentin Chappron, edited by Kate Entringer)