A 19-year-old French woman committed suicide by throwing herself in front of a suburban train in Paris and streamed the act live on Periscope.
French prosecutors have opened an investigation into the circumstances of the suicide on Wednesday.
The unnamed French woman "sent a text to one of her friends several minutes before her death to make them aware of her intentions," Prosecutor Eric Lallement said, according to the AFP.
"She also made statements to Internet users via the Periscope application to explain her act," he added.
Although the footage of the woman's actual death was removed by Periscope, some of the video leading up to the suicide was still available on YouTube. The incident took place on Tuesday at a station in Egly to the south of Paris.
The victim is seen sitting on a couch, smoking a cigarette and saying that the video is "not designed to create a buzz ... but to make people react, to open their minds, and nothing else". Immediately after this the video cuts to a black screen and one can faintly hear the voices of emergency personnel. Several concerned messages from Periscope users are seen flashing up on the screen.
"We were alerted around 4.30pm by a Periscope user who was connected with the victim and told us that she was not well," a police source said.
Periscope is a smartphone application that allows users to stream live video via their Twitter account. The video usually remains accessible for 24 hours. Twitter has said that it did not comment on individual accounts.
Prosecutor Eric Lallement said: "Once the first results of the analysis of the victim's mobile telephone and the images diffused by Periscope are known, the investigators will attempt to specify the motivations for her act, and if necessary, to enlarge the investigation."
Live-streaming of disturbing content has increasingly become commonplace. Last month, an 18-year-old woman appeared in court in the US state of Ohio for filming the rape of her 17-year-old friend by a 29-year-old man and live-streaming it on Periscope.